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| -rw-r--r-- | macros/polystab.sci | 53 |
1 files changed, 35 insertions, 18 deletions
diff --git a/macros/polystab.sci b/macros/polystab.sci index 84e42d4..c9da6f0 100644 --- a/macros/polystab.sci +++ b/macros/polystab.sci @@ -1,21 +1,38 @@ -function b = polystab(a) -//This function stabilizes the polynomial transfer function. -//Calling Sequence -//b = polystab(a) -//Parameters -//a: -//Description -//This is an Octave function. -//This function stabilizes the polynomial transfer function by replacing all roots outside the unit circle with their reflection inside the unit circle. -//Examples +function y = polystab(x) +//Stabilize the polynomial transfer function. +//Calling Sequence: +//y = polystab(x) +//Parameters: +//x: real or complex valued vector +//Description: +//This function stabilizes the polynomial transfer function by replacing all +//roots outside the unit circle with their reflection inside the unit circle. +//Example: //polystab([1,3,5]) -//ans = -// 1. 0.6 0.2 +//ans= +//[1, 0.6, 0.2] + + funcprot(0); + if (argn(2) ~= 1) + error("polystab: wrong number of input arguments"); + end + root = roots(x); + vals = find(abs(root) > 1); + root(vals) = 1 ./ conj(root(vals)); + b = x(1) * poly(root, 'x'); + y = flipdim(coeff(b), 2); + if (isreal(x)) + y = real(y); + end -funcprot(0); -rhs = argn(2) -if(rhs~=1) -error("Wrong number of input arguments.") -end -b = callOctave("polystab",a) endfunction + +//input validation: +//assert_checkerror("polystab()", "polystab: wrong number of input arguments"); +//assert_checkerror("polystab(1, 2)", "Wrong number of input arguments.") + +//tests: +//assert_checkalmostequal(polystab([1, 3, 5]), [1, 0.6, 0.2], %eps); +//assert_checkequal(polystab([1; 3; 5]), polystab([1, 3, 5])); +//assert_checkalmostequal(polystab([1+3*%i, 4+2*%i, 2+2*%i]), [1 + 3*%i, 1.35664 + 1.84888*%i, 0.88566 + 0.88566*%i], 5*10^-5); +//assert_checkalmostequal(polystab([-1; 3+%i; -2-6*%i]), [-1, 0.3 + 0.4*%i, -0.05-0.15*%i], 5*10^-5); |