Equation stored in variable, then used by Solver

[Han]

You can save the equation in a string. Likewise, I would consider a separate string for the variables.

E.g.

Code:


// formula: F=ma; we'll use the global variable F and create m and a as needed
vars:={ "m", "a" }; 
eqns:="F=m*a";

// initialize solver
local cmd,i, n:=SIZE(vars);

for i from 1 to n do
  cmd:=vars(i) + ":=0"; // set initial value to 0;
  CAS(cmd); // call CAS to evaluate cmd as if run from command line
end;

E1:=eqns; // set E1

// … code here to start the app, see STARTAPP() or STARTVIEW()

// clean up, if needed
for i from 1 to d no
  cmd:="purge(" + vars(i) +")"; // create a purge command
  CAS(cmd); // purge the variable
end;

These routines can easily to combined into a solver app to build an actual equation library with complete support for custom equations and variables. I'm currently working on one, but have been sidetracked with several other projects…