https://mediawiki.zeropage.org/index.php?action=history&feed=atom&title=CubicSpline%2F1002%2FTriDiagonal.py 2026-05-16T22:35:22Z Revision history for this page on the wiki MediaWiki 1.39.8 https://mediawiki.zeropage.org/index.php?title=CubicSpline/1002/TriDiagonal.py&diff=31025&oldid=prev 2021-02-07T05:23:03Z

<p></p> <p><b>New page</b></p><div> <br /> from LuDecomposition import *<br /> from Numeric import *<br /> from ArrayPrinter import *<br /> import pdb<br /> <br /> def getMatrixY(aMatrixLower, b):<br /> matrixY = makeEmptyMatrix(len(b),1)<br /> for n in range(len(b)):<br /> matrixY[n][0] = float(b[n][0] - _minusForGetMatrixY(n, aMatrixLower, matrixY)) / float(aMatrixLower[n][n])<br /> return matrixY<br /> <br /> def getMatrixX(aMatrixUpper, y):<br /> limitedMatrix = len(y)<br /> matrixX = makeEmptyMatrix(limitedMatrix,1)<br /> for n in range(limitedMatrix-1, -1,-1):<br /> matrixX[n][0] = float(y[n][0] - _minusForGetMatrixX(n, aMatrixUpper, matrixX)) / float(aMatrixUpper[n][n])<br /> #print &quot;x[%d]: y[%d][0] - minus:[%f] / u[%d][%d]:%f : %f&quot;% (n,n,_minusForGetMatrixX(n, aMatrixUpper, matrixX),n,n, aMatrixUpper[n][n], matrixX[n][0])<br /> return matrixX<br /> <br /> def _minusForGetMatrixX(n, aUpperMatrix, aMatrixX):<br /> totalMinus = 0<br /> limitedMatrix = len(aMatrixX)<br /> for t in range(n+1,limitedMatrix):<br /> totalMinus += aUpperMatrix[n][t] * aMatrixX[t][0]<br /> return totalMinus<br /> <br /> def _minusForGetMatrixY(n, aLowerMatrix, aMatrixY):<br /> totalMinus = 0<br /> for t in range(n):<br /> totalMinus += aLowerMatrix[n][t] * aMatrixY[t][0]<br /> return totalMinus<br /> <br /> <br /> def makeEmptyMatrix(aRow, aCol):<br /> emptyMatrix = []<br /> for i in range(0,aRow):<br /> emptyRow = []<br /> for j in range(0,aCol):<br /> emptyRow.append(0.0)<br /> emptyMatrix.append(emptyRow)<br /> return emptyMatrix<br /> <br /> def prettyPrintMatrix(aMatrix):<br /> print array2string(array(aMatrix))<br /> def printSeparator():<br /> print &quot;*-&quot; * 35<br /> <br /> if __name__==&quot;__main__&quot;:<br /> a = [[4.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],<br /> [1.0, 4.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],<br /> [0.0, 1.0, 4.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0],<br /> [0.0, 0.0, 1.0, 4.0, 1.0, 0.0, 0.0, 0.0, 0.0],<br /> [0.0, 0.0, 0.0, 1.0, 4.0, 1.0, 0.0, 0.0, 0.0],<br /> [0.0, 0.0, 0.0, 0.0, 1.0, 4.0, 1.0, 0.0, 0.0],<br /> [0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 4.0, 1.0, 0.0],<br /> [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 4.0, 1.0],<br /> [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 4.0]]<br /> b = [[5.0], [6.0], [6.0], [6.0], [6.0], [6.0], [6.0], [6.0], [5.0]]<br /> l, u = LuDecomposition(a).perform()<br /> printSeparator()<br /> print &quot;LuDecomposition - Matrix L:&quot;<br /> prettyPrintMatrix(l)<br /> #pdb.set_trace()<br /> printSeparator()<br /> matrixY = getMatrixY(l, b)<br /> print &quot;Calculated - Matrix Y&quot;<br /> prettyPrintMatrix(matrixY)<br /> printSeparator()<br /> print &quot;LuDecomposition - Matrix U:&quot;<br /> prettyPrintMatrix(u)<br /> printSeparator()<br /> print &quot;Final - Matrix X&quot;<br /> matrixX = getMatrixX(u, matrixY)<br /> prettyPrintMatrix(matrixX)</div>

imported>Unknown