parallel Definition and Topics - 46 Discussions

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. Engineering Finding the bandwidth of a parallel RLC circuit (+MATLAB)

Homework Statement The attempt at a solution Constructing the total impedance of the circuit as follows, $$\frac{1}{Z_T}=\frac{1}{Z_R}+\frac{1}{Z_C}+\frac{1}{Z_L}$$ where $Z_R=R$, $Z_C=-j\frac{1}{\omega C}$ and $Z_L=j\omega L$. $$\frac{1}{Z_T}=\frac{1}{R}+j\omega C+\frac{1}{j\omega L}$$...
2. I Difference between parallel and antiparallel spins?

What is the difference between parallel and antiparallel spins for a pair of nucleons? My understanding is that nucleons have a strong tendency to pair - proton with proton, neutron with neutron, proton with neutron. When they pair their spins either: cancel (spins pair antiparallel) pairing...
3. Is the source in parallel or series with the resistor?

Thank you for your time and effort. It is much appreciated. 1. Homework Statement I have attached the problem with the solution to this thread. Basically, the problem asks to construct the circuit model for a generic device by using the data of terminal current and voltage measurements. From...
4. Parallel vacuum sources

I have two vacuum sources each pulling 1 inHG. If I connect the vacuum sources to a Y-connector, with identical sized hoses, so that each pulls on one tip of the Y, will I get 2 inHG vacuum on the remaining hose, or will I get 1 inHG with more cfm? Thank you, B
5. Voltage in parallel V1=V2=V3

Homework Statement I have to write about voltage within a parallel circuit and the formula for voltage in parallel is Vt=V1=V2=V3. But I was wondering if that's only the case if the resistors have the same resistance becasue I used resistors with different values Homework Equations V1=V2=V3...
6. I need some help with vectors please

Homework Statement A(-4,-4), B(4,-2) and D(-2,2) a) Determine AB and AD vector My answer: AB=[8,2] and AD=[2,6] b) A point C is determined by DC being parallel to AB and the angle ABC = 90. Calculate the coordinates of C. I found out that C=(46/17, 54/17) c) Another point E has the...
7. Disconnected vs Connected parallel plate capacitor

I am having a hard time understanding the whole idea behind and the difference between disconnected vs connected parallel plate capacitor in terms of voltage and charge. How does this relate to the formula C(Q/V)=ke0A/d?
8. One 160 kW motor vs two 129 kW motors

This is related to steel wire pulling machine. I have 2 cases. In CASE-1: ONE MOTOR 160 kW AND CASE-2: TWO MOTORS 129 kW Each. i.e 2x129 kW Which case would have an efficient pulling force and efficiency Case 1 or Case 2.
9. The magnetic flux density at point P between parallel wires

Homework Statement In the picture at points A and B are two thin parallel wires, where travelling currents are 15 A and 32 A to opposite directions. The distance between wires is 5.3 cm. Point's P distances from A and B are the same. Calculate the magnetic flux density at point P. Homework...
10. Gauss's Law and Parallel Line Charges

Homework Statement Find an equation for the net electric field at a point, above and between, two infinite line charges, one with line charge density λ and the second with line charge density -λ. The point is a distance R from both line charges, a distance y above the midpoint between charges...
11. B Correlation between black holes and parallel universes.

I'd like to know people's views on the possibilty of Black Holes being 'Gateways' or 'Portals' to parallel universes.
12. Source transformation, current & voltage sources

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown > Hi, I was working on a the source transformation and i got to the part where there are two current sources in the circuit. The current sources were added together (giving they were going in the...
13. The frequency of two parallel springs and one weight system

Homework Statement I want to find the angular frequency of the system below Homework Equations F = -kx U = 1/2*k*x^2 The Attempt at a Solution But here's the answer: I dont know how come this solution. Any one help me? Thank you so much.
14. B Stumped by the simplest geometry problem

Yes, one more reason to be humble, I know. This is the simplest problem I couldn't solve so far. Assume we have a circle of center O, a ruler of arbitrary size and a pencil. We use the ruler and the pencil to choose 4 points on the circle - the extremities of two diametral/diagonal segments...
15. Batteries connected in parallel - Amps won´t add up?

Batteries are connected in parallel. Multimeter shows: 1,5V AND... "0.12A" regardless of battery number. Volts stay the same but should not Amps add up in parallel? "0.12A" with 4, 5 or 6 batteries... Details: Amps measured correctly by closing the circuit with multimeter probes (bulb lights...
16. Motors in series: how do you stop one motor from spinning?

Hi All, I've been reading up on hybrid vehicles and how the Honda Insight has an electric motor attached directly to the gas engine driveshaft. Their combined output causes the wheels to spin. My question is in regards to when the electric motor is off but the gas engine is on. Why doesn't the...
17. Fault analysis -- Simplifying to Thevenin equivalent

Homework Statement [/B] All voltages and impedances are in per unit values. After all the source transformations, why is the voltage source still 1 ? Homework Equations The Attempt at a Solution [/B]
18. Let A, B, and C be vectors in R3...prove r lies in a plane

Homework Statement ##\vec { \dot { r } } =(t+1)\vec { A } +(1-sint)\vec { B } \quad \vec { r(0) } =\vec { C } ## a. Find an equation of the tangent line to the curve at ##\vec { r(0) } =\vec { C } ##. b. Use a definite integral to find ##\vec { r(t) } ## c. If ##A## and ##B## are non...
19. Find the equation of the plane parallel to two lines

Homework Statement Let A, B and C be distinct vectors in V3 with B and C non-parallel. a. Find an equation for the plane containing both the line through A parallel to B and the line through A parallel to C. b. Verify that the two lines actually lie in the plane. Homework Equations The...
20. Parallel flow exercise

Homework Statement I would really appreciate if you could give me some hints regarding what exactly to iii) Homework Equations we know they are in parallel so Q=Q1+Q2+.....+Qn delta hloss=delta hloss1+deltahloss2+...... delta P=delta P1=delta P2=...... The Attempt at a Solution We know flow...
21. Engineering Simplifying a Circuit w/ Parallel Resistors

The goal of this problem is to find the equivalent resistance of all the resistors. Each resistor shown in the image has a conductance of 1 mS which I believe is equal to 1000 ohms. I attached a picture of the circuit diagram in which I show some of my work in order to convey my erroneous...
22. Kirchoff's method for a weird circuit

Homework Statement In the following circuit, the battery has emf ε = 12.7 V. The resistors are R1 = 2000 Ω . R2 = 3000 Ω, and R3 = 4000 Ω. What is the current through resistor R2 ? Homework Equations Kirchoff's Rules V=IR The Attempt at a Solution i0 (into A) - i2 (current into resistor 2) -...
23. Circuit question: Find size and direction of current at P

Homework Statement Homework Equations I = I1 + I2 ... + In R = R1 + R2 ... + Rn 1/R = 1/R1 + 1/R2 ... + 1/Rn The Attempt at a Solution Let I1 = I2 + I3 where I1 is the current on the top wire, I2 the current on the middle wire and I3 the current on the bottom wire. 4 = 10I2 + 20I1 //This...
24. Parallel and Series Capacitors?

In the figure below, a potential difference V = 150 V is applied across a capacitor arrangement with capacitances C1 = 12.0µF, C2 = 6.00µF, and C3 = 16.0µF. Find the following values. Here's the diagram: http://www.webassign.net/hrw/hrw7_25-28.gif I already solved this problem but I'm having...
25. Parallel Buck Converters

I have a ton of 1A buck converters, and have a 5A application in which i need to run. I do not want to order any new buck converters, because I already have so many 1A ones, and do not have money for any new ones. Each one can only handle 1A before it over heats. I was wondering if I could use...
26. Ax+by=c is a straight line. When b=0 then it is // to y-axis

Am I forgetting some critical basic knowledge? It says: In the plane (identified by R^2) a linear equation ax+by=c is a straight line. If b=0 then this straight line is parallel with the y-axis; in the other case it is a straight line with slope -a/b. A (2 by 2)-system linear equation. Why is...
27. Why don't all lights turn off when connected in parallel

Homework Statement When the filament of a light is broken why do others continue to light? Homework Equations Parallel: U=U1=U2=U3 I=I1+I2+I3+... The Attempt at a Solution Is it because there are some nodes? How can you explain this simply?
28. Difference between lights connected in series and parallel

Homework Statement When two same lamps are connected with the same battery. Their lighting will be greater when they are connected in series or parallel? Homework Equations Series U=U1+U2+U3+... I=I1=I2=I3... Parallel U=U1=U2=U3... I=I1+I2+I3+... The Attempt at a Solution The answer is when...
29. Two voltage sources and two loads, how to approach this one

Homework Statement imgur link: http://i.imgur.com/G9RKEH1.png Homework Equations The Attempt at a Solution [/B] Should I just consider that A and B are parallel with each voltage source respectively and so therefore that's the voltage drop that they experience individually? The...
30. 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...