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Simplify some generalized math formulas: 

Now the 'sin^2+cos^2=1' and the 'sinh^2-cosh^2=-1' code can handle, for example: sin^4+cos^4=1, sinh^10-cosh^10=-1.
Also, the arguments can be also multitokens, so that it's possible to simplify, for example: 'sin^2(k())+cos^2(k())=1'.
This commit is contained in:
Edoardo Prezioso 2013-01-04 13:06:09 +01:00
parent 5485e6866f
commit 1c0c0471df
2 changed files with 39 additions and 8 deletions
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39
lib/tokenize.cpp
View File

@ -9350,14 +9350,37 @@ void Tokenizer::simplifyMathExpressions()
tok->str("0");
}
if (Token::Match(tok,"pow ( sin ( %any% ) , 2 ) + pow ( cos ( %any% ) , 2 )") && tok->strAt(4) == tok->strAt(14)) {
tok->deleteNext(18);
tok->str("1");
}
if (Token::Match(tok,"pow ( sinh ( %any% ) , 2 ) - pow ( cosh ( %any% ) , 2 )") && tok->strAt(4) == tok->strAt(14)) {
tok->deleteNext(18);
tok->str("-1");
//Pythagorean trigonometric identity: pow(sin(x),2n)+pow(cos(x),2n) = 1
//Hyperbolic identity: pow(sinh(x),2n)-pow(cosh(x),2n) = -1
//2n = any number which is multiple of 2
if (Token::simpleMatch(tok, "pow (")) {
if (Token::simpleMatch(tok->tokAt(2), "sin (")) {
Token *tok2 = tok->linkAt(3);
if (!Token::Match(tok2, ") , %num% ) + pow ( cos (") ||
MathLib::toLongNumber(tok2->strAt(2)) % 2 != 0)
continue;
Token *tok3 = tok2->tokAt(8);
if (!Token::Match(tok3->link(), ") , %num% )") ||
tok3->link()->strAt(2) != tok2->strAt(2))
continue;
if (tok->tokAt(3)->stringifyList(tok2->next()) == tok3->stringifyList(tok3->link()->next())) {
Token::eraseTokens(tok, tok3->link()->tokAt(4));
tok->str("1");
}
} else if (Token::simpleMatch(tok->tokAt(2), "sinh (")) {
Token *tok2 = tok->linkAt(3);
if (!Token::Match(tok2, ") , %num% ) - pow ( cosh (") ||
MathLib::toLongNumber(tok2->strAt(2)) % 2 != 0)
continue;
Token *tok3 = tok2->tokAt(8);
if (!Token::Match(tok3->link(), ") , %num% )") ||
tok3->link()->strAt(2) != tok2->strAt(2))
continue;
if (tok->tokAt(3)->stringifyList(tok2->next()) == tok3->stringifyList(tok3->link()->next())) {
Token::eraseTokens(tok, tok3->link()->tokAt(4));
tok->str("-1");
}
}
}
}
}

8
test/testtokenize.cpp
View File

@ -7725,6 +7725,10 @@ private:
" std::cout<<ln(1);\n"
" std::cout<<pow(sin(x),2)+pow(cos(x),2);\n"
" std::cout<<pow(sinh(x),2)-pow(cosh(x),2);\n"
" std::cout<<pow(sin(x*y+z),2)+pow(cos(x*y+z),2);\n"
" std::cout<<pow(sinh(x*y+z),2)-pow(cosh(x*y+z),2);\n"
" std::cout<<pow(sin(x),4)+pow(cos(x),4);\n"
" std::cout<<pow(sinh(x),10)-pow(cosh(x),10);\n"
"}";
const char expected1[] = "void foo ( ) {\n"
@ -7738,6 +7742,10 @@ private:
"std :: cout << 0 ;\n"
"std :: cout << 1 ;\n"
"std :: cout << -1 ;\n"
"std :: cout << 1 ;\n"
"std :: cout << -1 ;\n"
"std :: cout << 1 ;\n"
"std :: cout << -1 ;\n"
"}";
ASSERT_EQUALS(expected1, tokenizeAndStringify(code1));