\sqrt from another font

Question

I'm trying to change a specific char in my math collection: the square root symbol, as you can see below:

I'm trying to do it via \DeclareMathSymbol{\sqrt}... , but I can't determine witch parameters I have to enter.

The square root symbol that I want is available using the utopia option with the mathdesign package.

Any ideas?

Answer 1

You have to define new symbol fonts; the relevant declarations are

\DeclareSymbolFont{mdputsymbols}{OMS}{mdput}{m}{n}
\DeclareSymbolFont{mdputlargesymbols}{OMX}{mdput}{m}{n}    
\DeclareMathRadical{\sqrtsign}{mdputsymbols}{"70}{mdputlargesymbols}{"70}

Here's an example; the two \let instructions are to keep the old symbol for doing a comparison. In the output, the new one (Utopia based) is on the left.

\documentclass{article}
\let\oldsqrtsign\sqrtsign
\DeclareSymbolFont{mdputsymbols}{OMS}{mdput}{m}{n}
\DeclareSymbolFont{mdputlargesymbols}{normal}{OMX}{mdput}{m}{n}    
\DeclareMathRadical{\sqrtsign}{mdputsymbols}{"70}{mdputlargesymbols}{"70}

\begin{document}

$\sqrt{abc}$
{\let\sqrtsign\oldsqrtsign$\sqrt{abc}$}

\end{document}

Notice that this uses up two font alphabets (there are only 16 available), just for that symbol. It's not avoidable, as radicals need to be taken from a math font.