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inpptree.c, polish comments

This commit is contained in:
rlar 2012-04-05 21:24:48 +02:00
parent 42653f7c3d
commit 9a75774e36
1 changed files with 17 additions and 19 deletions
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36
src/spicelib/parser/inpptree.c
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@ -219,10 +219,10 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
break;
case PT_POWER:
/* Two cases... If the power is a constant then we're cool.
* Otherwise we have to be tricky.
*/
if (p->right->type == PT_CONSTANT) {
/*
* D(f^C) = C * f^(C-1) * D(f)
*/
arg1 = PTdifferentiate(p->left, varnum);
newp = mkb(PT_TIMES, mkb(PT_TIMES,
@ -231,8 +231,10 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
mkcon(p->right->constant - 1))),
arg1);
} else {
/* This is complicated. f(x) ^ g(x) ->
* exp(y(x) * ln(f(x)) ...
/*
* D(f^g) = D(exp(g*ln(f)))
* = exp(g*ln(f)) * D(g*ln(f))
* = exp(g*ln(f)) * (D(g)*ln(f) + g*D(f)/f)
*/
arg1 = PTdifferentiate(p->left, varnum);
arg2 = PTdifferentiate(p->right, varnum);
@ -242,9 +244,7 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
mkb(PT_PLUS,
mkb(PT_TIMES, p->right,
mkb(PT_DIVIDE, arg1, p->left)),
mkb(PT_TIMES, arg2, mkf(PTF_LN, /*arg1*/p->left))));
/*changed by HT, '05/06/29*/
mkb(PT_TIMES, arg2, mkf(PTF_LN, p->left))));
}
break;
@ -279,7 +279,6 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
*/
switch (p->funcnum) {
case PTF_ABS: /* sgn(u) */
/* arg1 = mkf(PTF_SGN, p->left, 0); */
arg1 = mkf(PTF_SGN, p->left);
break;
@ -349,7 +348,6 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
break;
case PTF_EXP: /* exp(u) */
/* arg1 = mkf(PTF_EXP, p->left, 0); */
arg1 = mkf(PTF_EXP, p->left);
break;
@ -480,10 +478,10 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
p->left: ',' p->left->left: a p->left->right: b
*/
/* Two cases...
The power is constant
*/
if (p->left->right->type == PT_CONSTANT) {
/*
* D(f^C) = C * f^(C-1) * D(f)
*/
arg1 = PTdifferentiate(p->left->left, varnum);
newp = mkb(PT_TIMES, mkb(PT_TIMES,
@ -492,9 +490,11 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
mkcon(p->left->right->constant - 1))),
arg1);
} else {
/* This is complicated. f(x) ^ g(x) ->
exp(y(x) * ln(f(x)) ...
*/
/*
* D(f^g) = D(exp(g*ln(f)))
* = exp(g*ln(f)) * D(g*ln(f))
* = exp(g*ln(f)) * (D(g)*ln(f) + g*D(f)/f)
*/
arg1 = PTdifferentiate(p->left->left, varnum);
arg2 = PTdifferentiate(p->left->right, varnum);
newp = mkb(PT_TIMES, mkf(PTF_EXP, mkb(PT_TIMES,
@ -503,9 +503,7 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
mkb(PT_PLUS,
mkb(PT_TIMES, p->left->right,
mkb(PT_DIVIDE, arg1, p->left->left)),
mkb(PT_TIMES, arg2, mkf(PTF_LN, /*arg1*/p->left->left))));
/*changed by HT, '05/06/29*/
mkb(PT_TIMES, arg2, mkf(PTF_LN, p->left->left))));
}
arg2 = PTdifferentiate(p->left->left, varnum);
newp = mkb(PT_TIMES, arg1, arg2);