for i in *.txt; do cp “$i” “$i.backup”; done

On Windows this is even simpler. There you can simply do:

copy *.txt *.txt.backup

• Esthetics of process control have been lost (mostly academic interest).
• Optimization-based results are hard to understand in terms of physics (this is a “real” problem).

The loss of esthetics makes life less enjoyable. The loss of a physical undertanding of the technologies we employ makes life dangerous. If we use optimization technologies to push boundaries and improce profitability, we might be approaching an operating policy that is not very robust. This means that we have increased the risk of a system failure, and this risk may be hidden behind the complexity of the solution that optimization has given us.

I feel the golden mean has its place in modern operating policies. Optimization may very well guide process and control system design – but implementations should be avoided when fundamental physical characteristics of the optimal point are not completely understood.

See for yourself: help quadv

BTW – I got this from the Jan 16 issue of New Scientist. It just nagged me enough to write this post here…

import sympy
[x1,x2,x3,x4]=sympy.symbols(['x1','x2','x3','x4'])
A=sympy.Matrix([[x1,x2],[x3,x4]])

Now, say you want to populate this matrix with x1=x2=x3=x4=1. This is easy:

An=A.subs({x1:1,x2:1,x3:1,x4:1})

Convert to numpy array:

from pylab import array
B=array(An)

This works….., but we have an array of objects, not of floats! Hm… The sympy module gives us the evaluate expression function N:

B_float = array(sympy.N(An))

Hm… fails again, with the error “Not implemented for matrices” (or something like that). So what do we do now? Well, we can iterate over An and apply this to each element. The following function does the job:

def Sym2NumArray(F):
“”"Function to convert symbolic expression with numerical data to numpy array “”"
shapeF=shape(F)
B=zeros(shapeF)
for i in range(0,shapeF[0]):
for j in range(0,shapeF[1]):
B[i,j]=sympy.N(F[i,j])
return B

Enjoy

One company has seen a potential profit in this and created a Mathtype-To-Equation software, which is an add-in to word that can convert MathType to Microsoft Equation 3.x (and to the new equation format in Word 2007, but that does not help us). The nice thing is that OpenOffice.org can convert Microsoft Equation objects.

The software is found at grindeq.com . It is not free, but comes with a trial version that allows 10 launches. I tried it on a fairly long and complicated document (15 pages, 70 equations) and it worked perfectly in OpenOffice.org Writer afterwards. Only too bad this costs money, as it should have been part of the MathType program itself (store in old format).

Enjoy!