Re: Can Mathematica invert large complex arrays ( 700x700)?---in a timely way that is

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Re: Can Mathematica invert large complex arrays ( 700x700)?---in a timely way that is*From*: mek at guinan.psu.edu (Mark E. Kotanchek)*Date*: Fri, 15 May 92 09:27:18 EDT

Since David Jacobson did all the work of determining a function to answer this question: Gregory Lampshire asks about the time required to invert a 700x700 array in Mathematica. I just did the following on an HP 9000/877 (snakes processor). In[13]:= Timing[Inverse[Table[Random[],{700},{700}]]]//First Out[13]= 315.05 Second The Timing command returns a list consisting of the time and the answer. First grabs the time and throws away the answer, since I didn't want my screen cluttered with 490000 numbers. I did this after a whole day of working with mathematica. It pushed the virtual memory consumption up to 50144K. I'm not sure how much I had consumed up to the point where I did this example, but it probably wasn't over 15 MB. I plugged in David's function and ran it on my NeXTstation (monochrome, 32 MB RAM) and came out with a result of: 532.867 Second I noticed a reasonable amount of disk access during this processing. I ran the command a second time with Mathematica as "first responder" and "warmed up" and got a result of 520. Second So, for what it's worth, enjoy. Later, Mark. --- Mark Kotanchek Guidance & Control Dept - 363 ASB Applied Research Lab/Penn State P.O. Box 30 State College, PA 16804 e-mail: mek at guinan.psu.edu (NeXTmail) TEL: (814)863-0682 FAX: (814)863-7843