MATLAB: What is the concept behind symbolic toolbox

symbolic toolbox

Using normal command we can not calculate factorial(200), it gives inf, but using symbolic toolbox we are able to calculate factorial (sym(200)),

My question is how symbolic toolbox is able to calculate whereas normally we cant, what is the concept behind this

Best Answer

MATLAB uses hardware instructions to calculate most of the basic operations; those hardware instructions work on fixed-length binary numbers, such as hardware addition, hardware division, and so on.

The symbolic toolbox does not use fixed length binary numbers. The symbolic toolbox uses chains of blocks to represent numbers. Instead of using hardware instructions to do the basic operations, it calculates everything in software, using slower libraries that handle the chains of data.

Related Solutions

MATLAB: Stl export for geometry from pointcloud/array

I should start this answer with 'I have no idea what I'm doing here'. I found your question interesting and have had a go at it with a combination of googling and experimentation. As such, this may be a terrible way to proceed but I seem to have got somewhere

The first complication is that there are at least two stlwrite functions:

Official MATALB one: https://uk.mathworks.com/help/matlab/ref/stlwrite.html
One on the FEX: https://uk.mathworks.com/matlabcentral/fileexchange/20922-stlwrite-write-ascii-or-binary-stl-files

. I think that your forum posts were referring to the FEX version which is older. For what follows, I use the FEX version

d = [0 1];
[x,y,z] = meshgrid(d,d,d); % a cube
x = [x(:);0];
y = [y(:);0];
z = [z(:);0];
stlwrite('Quader.stl',boundary(x,y,z),[x,y,z],'mode','ascii');

I used a free stl viewer to look at the result and the wireframe returned was

I chose ASCII output so we can look at it. Probably want to use binary output (the default) for big files. The contents of the file are

solid Created by stlwrite.m 13-Oct-2020 16:32:19
facet normal 0.0000000E+00 0.0000000E+00 -1.0000000E+00
outer loop
vertex 0.0000000E+00 0.0000000E+00 0.0000000E+00
vertex 0.0000000E+00 1.0000000E+00 0.0000000E+00
vertex 1.0000000E+00 0.0000000E+00 0.0000000E+00
endloop
endfacet
facet normal 0.0000000E+00 -1.0000000E+00 0.0000000E+00
outer loop
vertex 0.0000000E+00 0.0000000E+00 1.0000000E+00
vertex 0.0000000E+00 0.0000000E+00 0.0000000E+00
vertex 1.0000000E+00 0.0000000E+00 0.0000000E+00
endloop
endfacet
facet normal -1.0000000E+00 0.0000000E+00 0.0000000E+00
outer loop
vertex 0.0000000E+00 0.0000000E+00 1.0000000E+00
vertex 0.0000000E+00 1.0000000E+00 0.0000000E+00
vertex 0.0000000E+00 0.0000000E+00 0.0000000E+00
endloop
endfacet
facet normal -1.0000000E+00 -0.0000000E+00 -0.0000000E+00
outer loop
vertex 0.0000000E+00 1.0000000E+00 1.0000000E+00
vertex 0.0000000E+00 1.0000000E+00 0.0000000E+00
vertex 0.0000000E+00 0.0000000E+00 1.0000000E+00
endloop
endfacet
facet normal -0.0000000E+00 -1.0000000E+00 -0.0000000E+00
outer loop
vertex 1.0000000E+00 0.0000000E+00 1.0000000E+00
vertex 0.0000000E+00 0.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 0.0000000E+00 0.0000000E+00
endloop
endfacet
facet normal 0.0000000E+00 0.0000000E+00 1.0000000E+00
outer loop
vertex 0.0000000E+00 1.0000000E+00 1.0000000E+00
vertex 0.0000000E+00 0.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 0.0000000E+00 1.0000000E+00
endloop
endfacet
facet normal 1.0000000E+00 0.0000000E+00 0.0000000E+00
outer loop
vertex 1.0000000E+00 1.0000000E+00 0.0000000E+00
vertex 1.0000000E+00 0.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 0.0000000E+00 0.0000000E+00
endloop
endfacet
facet normal 0.0000000E+00 0.0000000E+00 -1.0000000E+00
outer loop
vertex 0.0000000E+00 1.0000000E+00 0.0000000E+00
vertex 1.0000000E+00 1.0000000E+00 0.0000000E+00
vertex 1.0000000E+00 0.0000000E+00 0.0000000E+00
endloop
endfacet
facet normal 0.0000000E+00 1.0000000E+00 0.0000000E+00
outer loop
vertex 0.0000000E+00 1.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 1.0000000E+00 0.0000000E+00
vertex 0.0000000E+00 1.0000000E+00 0.0000000E+00
endloop
endfacet
facet normal 1.0000000E+00 0.0000000E+00 0.0000000E+00
outer loop
vertex 1.0000000E+00 1.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 0.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 1.0000000E+00 0.0000000E+00
endloop
endfacet
facet normal -0.0000000E+00 1.0000000E+00 0.0000000E+00
outer loop
vertex 0.0000000E+00 1.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 1.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 1.0000000E+00 0.0000000E+00
endloop
endfacet
facet normal -0.0000000E+00 0.0000000E+00 1.0000000E+00
outer loop
vertex 0.0000000E+00 1.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 0.0000000E+00 1.0000000E+00
vertex 1.0000000E+00 1.0000000E+00 1.0000000E+00
endloop
endfacet
endsolid Created by stlwrite.m 13-Oct-2020 16:32:19

MATLAB: Is it possible to allow Bit to Integer Converter blocks to use word lengths of 32

This enhancement has been incorporated in Release 2007b (R2007b). For previous product releases, read below for any possible workarounds:

The ability to handle more than 31 bits per integer is not available in the Bit to Integer Converter block in the Communications Blockset.

To work around this issue, split the N-bit data into two (N/2)-bit numbers where (N/2) is less than 31 bits. Pass the two halves separately through the Bit to Integer Converter blocks which convert (N/2) bit data to an integer. Following this, left shift the top half by (N/2) bits and perform a Bitwise OR with the lower half. The resulting output is equivalent to using a single N-bit data Bit to Integer Converter block where N > 31.

The attached model, bit_to_int_32bits.mdl illustrates the above procedure to convert 32-bit data to an integer. As explained above, split the 32-bit integer into two 16-bit integers representing the top and bottom halves. Pass the two halves through two Bit to Integer Converter blocks. Following this, left shift the 16-bit integer representing the top half to make a 32-bit integer and perform a Bitwise OR operation with the other 16-bit integer to result in a 32-bit integer. The attached models, bit_to_int_64bits.mdl and bit_to_int_double.mdl illustrate the process of extending the above example to create a 64-bit Bit to Integer Coverter block and a 52-bit Bit to Integer Converter block, respectively.

Best Answer

Related Solutions

MATLAB: Stl export for geometry from pointcloud/array

MATLAB: Is it possible to allow Bit to Integer Converter blocks to use word lengths of 32

Related Question