Parallel Definition and 1000 Threads

Parallel computing is a type of computation in which many calculations or processes are carried out simultaneously. Large problems can often be divided into smaller ones, which can then be solved at the same time. There are several different forms of parallel computing: bit-level, instruction-level, data, and task parallelism. Parallelism has long been employed in high-performance computing, but has gained broader interest due to the physical constraints preventing frequency scaling. As power consumption (and consequently heat generation) by computers has become a concern in recent years, parallel computing has become the dominant paradigm in computer architecture, mainly in the form of multi-core processors.Parallel computing is closely related to concurrent computing—they are frequently used together, and often conflated, though the two are distinct: it is possible to have parallelism without concurrency (such as bit-level parallelism), and concurrency without parallelism (such as multitasking by time-sharing on a single-core CPU). In parallel computing, a computational task is typically broken down into several, often many, very similar sub-tasks that can be processed independently and whose results are combined afterwards, upon completion. In contrast, in concurrent computing, the various processes often do not address related tasks; when they do, as is typical in distributed computing, the separate tasks may have a varied nature and often require some inter-process communication during execution.
Parallel computers can be roughly classified according to the level at which the hardware supports parallelism, with multi-core and multi-processor computers having multiple processing elements within a single machine, while clusters, MPPs, and grids use multiple computers to work on the same task. Specialized parallel computer architectures are sometimes used alongside traditional processors, for accelerating specific tasks.
In some cases parallelism is transparent to the programmer, such as in bit-level or instruction-level parallelism, but explicitly parallel algorithms, particularly those that use concurrency, are more difficult to write than sequential ones, because concurrency introduces several new classes of potential software bugs, of which race conditions are the most common. Communication and synchronization between the different subtasks are typically some of the greatest obstacles to getting optimal parallel program performance.
A theoretical upper bound on the speed-up of a single program as a result of parallelization is given by Amdahl's law.

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  1. CheesyPeeps

    Resistance in Parallel Equation

    The formula to find the total resistance in a parallel circuit is 1/R=1/R1+1/R2+1/R3, but wouldn't it be easier to use R=1/(1/R1+1/R2+1/R3)? I've only ever seen the equation written like that once before, and I'm wondering if there's a reason as to why it's never really used?
  2. marciokoko

    Help with current flow, voltage, resistors in basic circuit

    Im reading this stack exchange question: http://electronics.stackexchange.com/questions/28897/how-to-choose-value-of-resistor-in-voltage-divider So there is a 5V circuit with 2-100 Ohm resistors that yields a voltage drop across the divide of 2.5V. The current through the circuit is 25mA...
  3. W

    Series voltage source vs parallel voltage source

    Power systems isn't my area of specialty and I've been doing some reading where it was stated that series voltage connections are safer than parallel connection. I don't fully understand why though. website address...
  4. David Gin

    Determing flow of a closed loop parallel pumping system

    Hi all, How would one go about determining the flow(GPM) of a closed loop parallel piping system. I believe this has to do with the pressure intake and outlet of the pump as I have a pump in the mentioned system rated at 4350GPM@50Hz but it is pumping at 4500 GPM at 37Hz, Thank you all for...
  5. gracy

    Earthing of a System of Parallel Metal Plates

    whenever any plate of system of parallel plates is earthed total charge on outer faces of the plates will become zero .Is it always true?or only in case of system of two plates?
  6. C

    Current Algebra: Find Current in Electric Circuit w/ 3 Resisters of R

    Homework Statement An electric circuit consists of 3 identical resistors of resistance R connected to a cell of emf E and negligible internal resistance. What is the magnitude of the current in the cell? (in the diagram two of the resistors are in parallel with each other then the other in...
  7. H

    I Parallel universes and randomness

    As you might know there is no such thing as true randomness, which means everything happens for a reason. Let's say everything with the exactly same input will always return the exactly same output if you repeat it, no matter if there is a computer or a human being. Much might seem random, but...
  8. D

    Is it possible to shift between parallel universes?

    I am new here and I have a question. Is it possible to shift between Everett's parallel universes in the form of your consciousness?
  9. S

    Cylinder parallel to a constant external B field

    Homework Statement A cylinder of permeability ##\mu## is placed in an external field ##B_0##. find the strength and direction of magnetic field inside the cylinder for: a) when axis of cylinder is parallel to external field. b) when axis of cylinder makes an angle ##\theta _0## with external...
  10. A

    How Does a Spherical Inclusion Affect Potential in a Parallel Plate Capacitor?

    Homework Statement Capacitor parallel plates separation $$d$$, potencial diference $$V_0$$, at the center there is a semi sphere of radius $r_0$. Find the potencial as function of position if $$d>>r_0$$ Homework Equations I think that relevant equation are Gauss Law The Attempt at a...
  11. X

    Parallel Plates, Capacitor and Dielectrics

    Homework Statement The parallel Plates of a capacitor have an area of 2.00 x 10-1m2 a separation distance of 1.00 X 10-2 m and are connected to a 3000 V power supply. The capacitor is then connected from the supply, and a dielectric is inserted between the plates. We find that the potential...
  12. vetgirl1990

    Applying the parallel axis theorem to find inertia

    Homework Statement Calculate the moment of inertia of a uniform rigid rod of length L and mass M, about an axis perpendicular to the rod through one end. Homework Equations Parallel axis theorem: I = Icm + MD2 Long thin rod with rotation axis through centre: Icm = 1/12 ML2 Long thin rod with...
  13. jcruise322

    When to use parallel axis theorem for objects....

    Homework Statement A uniform solid ball of mass m and radius R rolls without slipping down a plane inclined at an angle f above the horizontal. Find the frictional force and the acceleration of the center of mass.[/B]Homework Equations τ=I*α so: fs*r=I*a Mg-Fs=ma Moment of inertia for...
  14. A

    Quick question on Parallel RLC circuit (Conceptual)

    Homework Statement Even conceptual problem in the text: Consider a standard RLC circuit driven by an AC source in which the elements are in parallel. Construct a phasor diagram and develop an expression for the phase angle θ. Now remove the resistor from the circuit, can you still develop an...
  15. kostoglotov

    RC Circ, Capacitor charging Q....very lost

    Homework Statement Homework Equations Series: R_{eq} = R_1 + ... + R_n Parallel: R_{eq} = \left(\frac{1}{R_1} + ... + \frac{1}{R_n} \right)^{-1} Charging Capacitor: I = I_0 e^{-t/RC} Charging Capacitor: \Delta V_C = \varepsilon (1- e^{-t/RC}) Charge: Q = C \Delta V_C The Attempt at a...
  16. E

    Grounding parallel plate conductors

    Homework Statement So, I always make mistakes on problems such as this (the grounding part), so I'm hoping someone could really explain to me how the process works instead of just answering this particular problem. There are n large parallel plate conductors carrying charges Q1, Q2,... Qn...
  17. gracy

    Identifying series and parallel connections

    Homework Statement In the arrangement shown,find the equivalent capacitance between A and B. Homework Equations Capacitance in parallel ##C##=##C_1##+##C_2##The Attempt at a Solution Supplied solution says As,we can clearly see that ,capacitors 10μF and 20μF are connected between same points...
  18. C

    Are streamlines parallel in inviscid and irrotational flow

    Are fluid streamlines in an irrotational, but viscous, flow parallel? Or does the flow need to be both irrotational and inviscid?
  19. amind

    Charge distribution on the surfaces of parallel conducting s

    Problem: Consider two parallel and large sheets with a surface area . One has a charge and the other is uncharged. q | | | | | | | | | | What would be the electric fields on the three regions as divided by the sheets ? General solution to problems like as told...
  20. K

    Navier-Stokes equation for parallel flow

    Homework Statement [/B] Find an equation for the flow velocity of a river that is parallel to the bottom as a function of the perpendicular distance from the surface. Apply the boundary conditions given and solve, and find the velocity at the surface. Note that the coordinates are: x is the...
  21. Cynthesis

    Many Worlds - What drives the parallel branching?

    There is one segment of this interpretation that has always nagged at my mind. It's the part where a separate branch splits off at each individual choice. For a simple example; I have a choice to turn left or right, I choose to turn right, so now according to this interpretation another version...
  22. B

    Cauchy Schwarz equality implies parallel

    I'm learning about Support Vector Machines and would like to recap on some basic linear algebra. More specifically, I'm trying to prove the following, which I'm pretty sure is true: Let ##v1## and ##v2## be two vectors in an inner product space over ##\mathbb{C}##. Suppose that ## \langle v1 ...
  23. G

    Why Is y Bar Zero in the Parallel Axis Theorem for Area?

    Homework Statement why the y bar is 0 ? according to the diagram , y ' has certain value , it's not 0 ! can someone help to explain ? Homework EquationsThe Attempt at a Solution
  24. Tesladude

    Does Using Multiple 20mW Transmitters Increase Remote Control Car Range?

    I have built a remote control car, pwm speed controll and all, using picaxe microcontrollers and gained a lot of experience doing it. I used a low power i think 20mw transmitter you can find all over ebay that uses a 433hz carrier wave. A long time ago i found a 1w transmitter meant to be a step...
  25. ognik

    MHB Parallel Forces in Cartesian Coordinates

    Not sure I understand this question, which says: "Develop a condition when 2 forces are parallel, with & without using Cartesian co-ords." I think there must be a common normal between the 2, so that $ F_1.\vec{n} = 0 = F_2. (- \vec{n}) $ or $ (F_1 + F_2).\vec{n} = 0 $ - is that correct...
  26. S

    Size of current in parallel wires

    Homework Statement Two parallel wires are positioned at l = 2.76 cm apart. Initially a current I1 = 9.57 A flows up the screen through wire 1, and wire 2 has no current in it. A current is then sent through wire 2. The magnetic field between the two wires, is found to be 0T. What is the size...
  27. M

    Potential Difference between two parallel charged plates.

    How do we find out the potential difference between two equal and opposite charged (conducting) parallel plates mathematically? Let the charge on a plate be 'Q', Total area of a plate be 'A', the distance between the plates be 'd'. I need a direct mathematical solution please, I've come across...
  28. Adam LeTrexane

    A Addresses of Parallel Universes

    Hi there! Alright, so let me start off by saying I'm a biochemist by trade, but have an extreme (and possibly unhealthy) interest in the more bizarre aspects of modern physics. Admittedly, I don't understand the mathematical formalisms associated with the theories I know of, so bear with me if...
  29. T

    Understanding how to decompose series and parallel circuits

    I have uploaded an image of the situation I am looking at. Essentially, the Thevenin voltage is being found, and one thing I don't quite understand in this example is the text saying R2 can be neglected when trying to find the Thevenin voltage. It says R1 and R3 form a voltage divider, but I...
  30. DoobleD

    Solving a parallel LC circuit with DC current

    Take the following circuit (capacitor initially not charged) : I am trying to solve for the current everywhere as a function of time. I set up the following equations (are they right ?) : Then, any way I try it, I end up with some messy integrals. Even using wolfram alpha to get those...
  31. A

    Understanding the Effects of a Conducting Plate on a Parallel Plate Capacitor

    Homework Statement Consider a parallel plate capacitor of area A and separation d. The plates are isloated. One has charge +Q and the other -Q. An isolated conducting plate of area A and thickness t is inserted between the plates as shown. a. Find the E fields between the conductors b. Find...
  32. JulienB

    Determine components of a vector without knowing the angle

    Homework Statement (I roughly translate the problem statement from German) Given the vectors a = (1,-2,3) and b = (1,1,1), divide the vector a in two components a1 (parallel to b) and a2 (perpendicular to b). Homework Equations In a previous question of the problem, I found that: a.b = 2 a x...
  33. F

    First-order spring/damper system in parallel

    Homework Statement A viscous damper, with damping constant b, and a spring, with spring stiffness k, are connected to a massless bar. The bar is displaced by a distance of x = 0.1m when a constant force F = 500N is applied. The applied force F is abruptly released from its displaced position if...
  34. D

    Combine Resistors: Parallel Method to 1 Resistor

    Homework Statement Combine the resistors into one single resistor Homework Equations Resistors in parallel = 1/1/R1 + 1/R2 +1/R3... Resistors in series = add The Attempt at a Solution I have two ways of getting the resistance. One is by saying that the 80ohm is parallel 20ohm and then...
  35. D

    Understanding Charge Accumulation in Parallel Plate Capacitors

    Homework Statement My lecture notes say that no current flows through capacitors as the dielectric material is a poor conductor. It goes on to say that the capacitor appears as an open circuit to a DC voltage source. It then says that charge will accumulate on the plates with an equal amount of...
  36. H

    Two capacitors in parallel rearranged

    I just had a test, and I'm wondering how to do one of the free responses on it. The first couple parts, which I'll omit, were pretty simple, but I got kind of lost toward the end. Two Capacitors (C1=10microF C2=40microF) are connected in parallel to a 10V battery. The capacitors are then...
  37. thorq

    Parallel string walking between two threaded cylinders?

    Hello, I have a problem that seems to have beaten me. I want to make a cable-driven reduction system between a threaded rod (pinion) and a larger threaded cylinder. Because of string walking, the string between the two has to stay at all times straight, parallel to the ground so that...
  38. Rath123

    Calculating Time Constant in Parallel Plates: Keeping the Capacitor Constant

    How can a time constant, in parallel plates, be the original value without changing the capacitor?
  39. Rath123

    Is the Time Constant Affected by Changing Plate Distance in an RC Circuit?

    If, by some means, the distance between the parallel plates of the capacitor is reduced to half of what it was before, would the time constant change? If yes, then what would be the new time constant?
  40. P

    Dielectric inserted in parallel plate capacitor

    Homework Statement When a dielectric is partially inserted between two plates of a capacitor that is disconnected, what will be it's motion? Also what will be its motion if the capacitor is connected to a battery? Homework EquationsThe Attempt at a Solution For the first part. I think the...
  41. K

    Why does the current divide through parallel resistors

    why does the current divide through parallel resistors? In parallel both resistors have the same potential difference. So how does the charges know that they must go into the resistor with less resistance than other resistor? (sorry my bad english)
  42. D

    Drag force of a cylinder with it's axis parallel to the flow

    Hello, I would like to know how to calculate the drag force per unit length of an infinite cylinder with it's axis parallel to the flow field, I had read about a post here previously titled " Drag force on cylinder in parallel flow" but the slender body approximation is not valid for inifinite...
  43. B

    Why Does a Bulb Shine Brighter with Batteries in Series vs Parallel?

    I seem to lack a conceptual understanding of how batteries in series and parallel affect the brightness of a bulb. I understand that current adds when batteries are in parallel and that voltage adds when batteries are in series, but why does 2 batteries in series make a bulb more bright than two...
  44. BadgerBadger92

    B A Question About Parallel Universes....

    Keep in mind this is completely a theoretical question... In the end I know nothing about physics. I just have a question. If parallel universes exist, and two or more of them had the ability to travel time (If that were even possible at all. Doubtful.) could someone technically travel to this...
  45. S

    Why is the voltage across this parallel circuit positive?

    Homework Statement The problem along with its solution are attached in TheProblemAsWellAsSolution.jpeg file. For this post, I'm only referring to part (a), since part (b) is the same thing with another number. Homework Equations V = IR Parallel circuit: ##I = I_1 + I_2 + . . . + I_n## The...
  46. F

    Resistors in series, parallel or?

    Hello Forum, When resistors are introduced, it is explained that they can be either in series or in parallel configuration. In series means that the are traversed by the same current and one of the terminals of each resistor is connected to the other's terminal( I am saying that because there...
  47. P

    How to get a # out of moment of the parallel axis theorm

    The question is : four masses shown in figure 12.14 (Knight 12.14) are connected by massless, rigid rods. (see attached fig) A) find the coordinates of the center of mass B) find the moment of inertia about a diagonal mass that passed through B and D so I got part a right by setting the x-y...
  48. Brandon Hawi

    Cross Product of Parallel Vectors is the zero vector (why?)

    Hello, PF! I had a quick question that I hoped maybe some of you could help me answer. The question is simple: Why is the cross product of two parallel vectors equal to the zero vector? I can see this easily mathematically through completing the cross product formula with two parallel...
  49. Prof.gaming

    B A question about parallel universes I want to share

    Um ... yea. This was on my mind for a long time and was bugging me like hell , so I want to share it and ask if its correct or could be correct . My theory is , as we know , there are unlimited parallel universes , made by the Many-worlds interpretation . Sometimes the difference is unnoticeable...
  50. RelativeJosef

    Current and resistance in series and parallel circuits

    Homework Statement List the order of brightness of each bulb (while the switch is open) assuming the bulbs are all of the same resistance. Homework Equations Ohm's Law: Change in voltage = current divided by resistance The Attempt at a Solution I know that bulbs A,C,D,F are all equal in...
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