Compare analyzes the pair of expressions expression1 and expression2 and tries to find a best match between their corresponding operands such that in the resulting identification the operands which differ are of minimal size. It then displays these differences using various possible output formats.

For small expressions - both less than length 250 - or when the combine option is set to false, the two expressions will be printed one after the other in the output, with those subexpressions which have been determined to differ between them highlighted using a different color than the rest of the expressions.

Alternatively, for large expressions, or if combine is set to true, the two expressions will be combined into one, in essence glued at subexpressions which match. Where the subexpressions don't match, a vector of the two different corresponding subexpressions will appear instead, again with special colors highlighting the differences.

If a verification ver is supplied as an extra argument, then corresponding subexpressions x1 and x2 of expression1 and expression2 respectively which are found to satisfy verify(x1, x2, ver) are considered by Compare to be equivalent and their differences will thus be ignored.

There are various other options that control the format of the output when the two expressions are found to differ:

In the combined view, the vectors showing corresponding differences can be displayed without parentheses using the showvectorbrackets = false option.

In some cases a subexpression in one of expression1 or expression2 has no corresponding subexpression in the other with which to match; when this happens the vector will have just one entry, with only the color distinguishing whether it was a subexpression of expression1 or expression2. When this output may be confusing, the user can instead supply the additional option showNULLoperands, which forces display of both of the corresponding subexpressions even when one is missing. In this case the vector will contain an invisible entry making the position of the visible entry indicate which of expression1 or expression2 it is a subexpression of.

Supplying color1 and color2 as additional arguments controls the color highlighting for the corresponding subexpressions of expression1 and expression2 which differ.

By default (if the highlight option is not given, or if it is set to default), the foreground colours of subexpressions that differ will be changed for expressions which are small (as defined above). For large expressions, the background colour will be changed instead. By supplying the option highlight=foreground or highlight=background, these defaults can be overriden.

Compare uses the uneval parameter modifier. Providing the evaluate option tells Maple to fully evaluate expression1 and expression2 before computing and displaying their differences.

The default value of each Compare option can be queried and/or reset using the Options command, as can the defaults for the highlight colors and the length which triggers the combined view.

It is not recommended at this time to use this command in Maple's text-based interface.

$\mathrm{with}\left(\mathrm{ExpressionTools}\right)$

$\left[\mathrm{Compare}\,\mathrm{Options}\right]$

$\mathrm{x1}≔\left(2a-3b\right)\left(A-B\right)c$

$\mathrm{x1}≔\left(2a-3b\right)\left(A-B\right)c$

$\mathrm{x2}≔\left(3b-2a\right)\left(B-A\right)C$

$\mathrm{x2}≔\left(3b-2a\right)\left(B-A\right)C$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{x2}\right)$

$\left(2a+\mathrm{-3}b\right)\left(A+\mathrm{-1}B\right)c$

$\left(3b+\mathrm{-2}a\right)\left(B+\mathrm{-1}A\right)C$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{x2}\,\mathrm{sign}\right)$

$\left(2a-3b\right)\left(A-B\right)c$

$\left(3b-2a\right)\left(B-A\right)C$

$\mathrm{x3}≔\mathrm{subs}\left(C=c\,\mathrm{x2}\right)$

$\mathrm{x3}≔\left(3b-2a\right)\left(B-A\right)c$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{x3}\,\mathrm{sign}\right)$

$\mathrm{The\; expressions\; satisfy\; the\; given\; verification}$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{x2}\,\mathrm{combine}\right)$

$\left(\left(\begin{array}{c}2\\ \mathrm{-2}\end{array}\right)a+\left(\begin{array}{c}\mathrm{-3}\\ 3\end{array}\right)b\right)\left(\left(\mathrm{-1}\right)A+\left(\mathrm{-1}\right)B\right)\left(\begin{array}{c}c\\ C\end{array}\right)$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{x2}\,\mathrm{combine}\,\mathrm{showvectorbrackets}=\mathrm{false}\right)$

$\left(\begin{array}{c}2\\ \mathrm{-2}\end{array}a+\begin{array}{c}\mathrm{-3}\\ 3\end{array}b\right)\left(\mathrm{-1}A+\mathrm{-1}B\right)\begin{array}{c}c\\ C\end{array}$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{x2}\,\mathrm{combine}\,\mathrm{showvectorbrackets}=\mathrm{false}\,\mathrm{showNULLoperands}\right)$

$\left(\begin{array}{c}2\\ \mathrm{-2}\end{array}a+\begin{array}{c}\mathrm{-3}\\ 3\end{array}b\right)\left(\begin{array}{c}\\ \mathrm{-1}\end{array}A+\begin{array}{c}\mathrm{-1}\\ \end{array}B\right)\begin{array}{c}c\\ C\end{array}$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{x2}\,\mathrm{combine}\,\mathrm{showvectorbrackets}=\mathrm{false}\,\mathrm{highlight}=\mathrm{background}\right)$

$\left(\begin{array}{c}2\\ \mathrm{-2}\end{array}a+\begin{array}{c}\mathrm{-3}\\ 3\end{array}b\right)\left(\mathrm{-1}A+\mathrm{-1}B\right)\begin{array}{c}c\\ C\end{array}$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{x2}\,\mathrm{Gray}\,\mathrm{Brown}\right)$

$\left(2a+\mathrm{-3}b\right)\left(A+\mathrm{-1}B\right)c$

$\left(3b+\mathrm{-2}a\right)\left(B+\mathrm{-1}A\right)C$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{x2}\,\mathrm{combine}\,\mathrm{Silver}\,\mathrm{Gold}\,\mathrm{showvectorbrackets}=\mathrm{false}\,\mathrm{highlight}=\mathrm{background}\right)$

$\left(\begin{array}{c}2\\ \mathrm{-2}\end{array}a+\begin{array}{c}\mathrm{-3}\\ 3\end{array}b\right)\left(\mathrm{-1}A+\mathrm{-1}B\right)\begin{array}{c}c\\ C\end{array}$

$\mathrm{x4},\mathrm{x5}≔\mathrm{Vector}\left(2\,\left[w\left(x\right)\,z\left(x\right)\right]\right)=\mathrm{Vector}\left(2\,\left[\frac{1}{15}\exp \left(-x\right)\left(-15\mathrm{c\_\_1}+3\right)+\frac{1}{15}\left(10\mathrm{c\_\_2}+2\right)\exp \left(4x\right)-\frac{1}{3}\exp \left(x\right)\,\frac{1}{5}\exp \left(-x\right)\left(-1+5\mathrm{c\_\_1}\right)+\frac{1}{5}\exp \left(4x\right)\left(1+5\mathrm{c\_\_2}\right)\right]\right),\mathrm{Vector}\left(2\,\left[w\left(x\right)\,z\left(x\right)\right]\right)=\mathrm{Vector}\left(2\,\left[\frac{1}{15}\exp \left(-x\right)\left(-15\mathrm{\_C1}+3\right)+\frac{1}{15}\left(10\mathrm{\_C2}+2\right)\exp \left(4x\right)-\frac{1}{3}\exp \left(x\right)\,\frac{1}{5}\exp \left(-x\right)\left(\left(1+5\mathrm{\_C2}\right)\exp \left(5x\right)-1+5\mathrm{\_C1}\right)\right]\right)\:$

$\mathrm{Compare}\left(\mathrm{x4}\,\mathrm{x5}\right)$

$\left[\begin{array}{c}w\left(x\right)\\ z\left(x\right)\end{array}\right]=\left[\begin{array}{c}\frac{{\ⅇ}^{-x}\left(-15\left(\begin{array}{c}\mathrm{c\_\_1}\\ \mathrm{\_C1}\end{array}\right)+3\right)}{15}+\frac{\left(10\left(\begin{array}{c}\mathrm{c\_\_2}\\ \mathrm{\_C2}\end{array}\right)+2\right){\ⅇ}^{4x}}{15}-\frac{{\ⅇ}^x}{3}\\ \left(\frac{{\ⅇ}^{-x}\left(-1+5\mathrm{c\_\_1}\right)}{5}\right)+\frac{{\ⅇ}^{\left(\begin{array}{c}4\\ \mathrm{-1}\end{array}\right)x}\left(\left(1+\left(5\mathrm{\_C2}\right)\right)\left({\ⅇ}^{5x}\right)+5\left(\begin{array}{c}\mathrm{c\_\_2}\\ \mathrm{\_C1}\end{array}\right)+\left(\mathrm{-1}\right)\right)}{5}\end{array}\right]$

$\mathrm{x6},\mathrm{x7}≔\frac{a}{2}+\frac{b}{3}+\frac{c}{4},\frac{c}{5}+\frac{b}{6}+\frac{d}{7}\:$

$\mathrm{Compare}\left(\mathrm{x6}\,\mathrm{x7}\,\mathrm{combine}\right)$

$\left(\begin{array}{c}\frac{a}{2}\\ \frac{d}{7}\end{array}\right)+\left(\begin{array}{c}\frac{1}{3}\\ \frac{1}{6}\end{array}\right)b+\left(\begin{array}{c}\frac{1}{4}\\ \frac{1}{5}\end{array}\right)c$

$\mathrm{v1}≔⟨1\,2⟩$

$\mathrm{v1}≔\left[\begin{array}{c}1\\ 2\end{array}\right]$

$\mathrm{v2}≔⟨1\,2⟩$

$\mathrm{v2}≔\left[\begin{array}{c}1\\ 2\end{array}\right]$

$\mathrm{evalb}\left(\mathrm{v1}=\mathrm{v2}\right)$

$\mathrm{false}$

$\mathrm{Compare}\left(\mathrm{v1}\,\mathrm{v2}\right)$

$\mathrm{The\; expressions\; are\; the\; same}$

$\mathrm{x8},\mathrm{x9}≔'\mathrm{hypergeom}\left(\left[a\,b\right]\,\left[c\right]\,x\right)','\mathrm{hypergeom}\left(\left[b\,a\right]\,\left[c\right]\,x\right)'$

$\mathrm{x8},\mathrm{x9}≔\mathrm{hypergeom}\left(\left[a\,b\right]\,\left[c\right]\,x\right),\mathrm{hypergeom}\left(\left[b\,a\right]\,\left[c\right]\,x\right)$

$\mathrm{Compare}\left(\mathrm{x8}\,\mathrm{x9}\right)$

$\mathrm{hypergeom}\left(\left[a\,b\right]\,\left[c\right]\,x\right)$

$\mathrm{hypergeom}\left(\left[b\,a\right]\,\left[c\right]\,x\right)$

$\mathrm{Compare}\left(\mathrm{x8}\,\mathrm{x9}\,\mathrm{evaluate}\right)$

$\mathrm{The\; expressions\; are\; the\; same}$

$\mathrm{Compare}\left(\mathrm{x1}\,\mathrm{subs}\left(C=c\,\mathrm{x1}\right)\,\mathrm{sign}\right)$

$\left(2a-3b\right)\left(A-B\right)c$

$\mathrm{subs}\left(C=c\,\mathrm{x1}\right)$

The ExpressionTools[Compare] command was introduced in Maple 2025.

For more information on Maple 2025 changes, see Updates in Maple 2025.