The entries that follow purposely exclude the high-end / expensive tools that designers are probably already familiar with.
Many people use MATLAB and C++ as their computational tools of choice, but there are quite a few alternatives available, many in open-source format. Here are a few leads to get the curious going:
Python with NumPy / Scipy
Python with matplotlib
Freemat (high degree of compatibility with MATLAB)
PTOLEMY out of UC Berkeley
Computation times can vary dramatically between software. As others have noted, most languages have a quirk or two about them and seemingly simple calculations can on occasion take forever. A skilled user can often navigate around these issues, so any benchmark comparisons like the ones that follow should be taken with a grain of salt.
For an example, we will consider is a simple case of solving the 2D Laplace equation using an iterative finite difference scheme (four point averaging, Gauss-Seidel or Gauss-Jordan). The formal specification of the problem is as follows. We are required to solve for some unknown function u(x,y) such that ∇2u = 0 with a boundary condition specified. For convenience the domain of interest is considered to be a rectangle and the boundary values at the sides of this rectangle are given.
It can be shown that this problem can be solved using a simple four point averaging scheme as follows. Discretise the domain into an (nx x ny) grid of points. Then the function u can be represented as a 2 dimensional array – u(nx, ny). The values of u along the sides of the rectangle are given. The solution can be obtained by iterating in the following manner.
for i in range(1, nx-1):
for j in range(1, ny-1):
u[i,j] = ((u[i-1, j] + u[i+1, j])*dy**2 + (u[i, j-1] + u[i, j+1])*dx**2)/(2.0*dx**2 + dy**2))
The rather remarkable computation times that were reported follow:
|Solution Method||Execution Time (sec)|
|Python + Psyco (estimate)||1138.0|
|Python + NumPy Expression||29.3|
Circuit Analysis & Simulation
LTspice IV (by Linear Technology) A remarkably capable analysis tool that is truly free.
Top Spice (I personally own and use this product and am pleased with it.)
RF & Microwave Filter Design
Digital Filter Design
Mixer Spurious Performance
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