Gdtyjr

I recently installed math professional II font (mtpro2 lite). It works fine except that the SQRT with root index sucks.

[ sqrt[100]1000000 = 1000 quad sqrt[3]1000000 = 100 ]

[ SQRT[100]1000000 = 1000 quad SQRT[3]1000000= 100 ]

Output

Is this a problem of the lite version (intended or not)? Does the complete version have this problem too? How can I define a new command to handle the situation automatically?

Don't know exactly why this fixes the problem, but it seems to. ;-)

documentclassarticle


usepackagemtpro2
usepackagemathtools

newcommandSQRTFIX[2][ ]hphantomscriptscriptstyle#1SQRT[mathllap#1]#2


begindocument

[ sqrt[100]1000000 = 1000 quad sqrt[3]1000000 = 100 ]

[
 SQRT[100]1000000 = 1000 quad SQRT[3]1000000 = 100 
]

[
 SQRTFIX[100]1000000 =1000 quad SQRTFIX[3]1000000 = 100 
 ]
enddocument

The second image simply shows in the yellow box what the original $SQRT$ does and in the blue box what $SQRTFIX$ does.

Thanks to @JPi’s amazing eyesight, I was able to track down exactly the bug in the mtpro2 package. All credits goes to him/her.

@JPi’s solution suggests that the offsetting space is somehow the width of the root index. I confirm this is the case. The root index is placed inside a box called rootbox. Here is how LaTeX defines its placement:

% From ltmath.dtx:
defr@@t#1#2%
 setboxz@hbox$m@th#1sqrtsign#2$%
 dimen@htz@ advancedimen@-dpz@
 mkern5muraise.6dimen@copyrootbox
 mkern-10muboxz@

which is the default, while mtpro2 does some similar things like:

% From mtpro2.dtx or mtpro2.sty
defR@@T#1#2setboxz@hbox$UPROOT@z@LEFTROOT@z@m@th#1SQR@@T#2$%
dimen@htz@advancedimen@-dpz@
dimen@iidimen@
setboxtw@hbox$m@th#1mskipUPROOT@ mu$advancedimen@ii by1.667wdtw@
setboxtw@hbox$m@th#1mskip10mu$%
ifcaseSQcount@advancedimen@3wdtw@oradvancedimen@1.5wdtw@or
advancedimen@wdtw@fi
mkern1mukern.13dimen@mkern-LEFTROOT@ mu
raise.5dimen@iicopyrootbox % was .44
mkern-1mukern-.13dimen@mkernLEFTROOT@ muboxz@kern-wdrootbox
LEFTROOTz@UPROOTz@

Focusing on the overall structures, we see immediately that R@@T has additional code of kern-wdrootbox, which IMHO is utterly wrong. So here is my fix:

documentclassarticle
usepackagenewtxtext
usepackagemtpro2% lite or complete, does not matter here

usepackageetoolbox
makeatletter
patchcmdR@@T
 kern-wdrootbox % search this within R@@T
 % replace it with nothing
 
makeatother

begindocument
[ sqrt[100]1000000 = 1000 quad sqrt[3]1000000 = 100 ]
[ SQRT[100]1000000 = 1000 quad SQRT[3]1000000 = 100 ]
enddocument

Note: sqrt and SQRT, by design, will produce slightly different results (as seen in the above picture). SQRT is supposed to be used for really large formulae (hence the awkward root index placement). Please refrain from using SQRT for small formulae.