# computer-algebra-systems

##### 在传递给 sum() 之前强制评估索引表达式(Force evaluate index expression before passing to sum())

2021-09-23 09:43:33    分类:技术分享    symbolic-math   quote   maxima   computer-algebra-systems

##### Force evaluate index expression before passing to sum()

I want to write an (somehow) enhanced sum function which takes a number of indices at once, but I cannot understand how to get it work. Here is what I currently have: (%i1) nsum(indexes, expr) := if indexes = [] then expr else nsum(rest(indexes), sum(expr, first(indexes),1, N)) \$ (%i2) nsum([i,j], i+j), nouns; sum: index must be a symbol; found intosym(first(indexes)) #0: nsum(indexes=[k,j],expr=k+j) I think this could be fixed by forcing Maxima expand first(indexes) into a symbol before passing to sum function. I tried ''(...) and ev(..., nouns), but without any success.

2021-09-03 18:48:01    分类:问答    symbolic-math   quote   maxima   computer-algebra-systems

##### Sympy：删除多项式中的高阶项(Sympy: Drop higher order terms in polynomial)

2021-09-01 07:25:23    分类:技术分享    python   sympy   symbolic-math   computer-algebra-systems   polynomials

##### 像 SymPy 这样的 Haskell 库？ [关闭](Haskell library like SymPy? [closed])

2021-06-22 21:12:37    分类:技术分享    haskell   symbolic-math   computer-algebra-systems

##### Equations Equality test (in C++ or with Unix tools) (algebra functions isomorphism) [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 5 years ago. Improve this question I am looking for C++ open-source library (or just open-source Unix tool) to do: Equality test on Equations . Equations can be build during runtime as AST Trees, string or other format. Equations will mostly be simple algebra ones, with some assumptions about unknown functions. Domain, will be integer arithmetic (no floating point issues, as related issues are well

2021-06-15 10:16:21    分类:问答    c++   math   open-source   discrete-mathematics   computer-algebra-systems

##### Symbolic Math Library in C/C++/Obj-C [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago. Improve this question I am trying to implement a graphing calculator on the iPhone. I am looking for a library that can take strings of expressions or functions and let me manipulate them (find derivatives, intercepts, zeros, etc). Does anything like this exist?

2021-06-10 20:48:25    分类:问答    c++   objective-c   c   symbolic-math   computer-algebra-systems

##### Sympy: Drop higher order terms in polynomial

Using Sympy, say we have an expression f, which is a polynomial of the Symbol "x" (and of potentially other symbols). I would like to know what if there is an efficient way to drop all terms in f of order greater than some integer n. As a special case I have a very complicated function but i want to only keep terms up to 2nd order in x. What's the efficient way to do this? The obvious, not-very-efficient way to do it would be for each m less than n, take m derivatives and set x to 0 to obtain the coefficient of x^m. We obtain each coefficient this way then reconstruct the polynomial. But

2021-06-05 02:31:58    分类:问答    python   sympy   symbolic-math   computer-algebra-systems   polynomials

##### 如何在 Sympy 中进行函数组合？(How to do function composition in Sympy?)

2021-06-01 15:54:38    分类:技术分享    python   sympy   computer-algebra-systems

##### Sympy中的多元泰勒近似(Multivariate Taylor approximation in sympy)

2021-05-25 02:59:34    分类:技术分享    python   sympy   computer-algebra-systems   symbolic-computation

##### 处理Sympy积分返回的分段方程(Dealing with piecewise equations returned by sympy integrate)

2021-05-18 06:59:43    分类:技术分享    python   sympy   symbolic-math   computer-algebra-systems   symbolic-computation