From help-octave-request at bevo dot che dot wisc dot edu Tue Jan 19 06:29:17 1999 Subject: Re: diff(x) question From: Joao Cardoso To: El Jeffo CC: help-octave at bevo dot che dot wisc dot edu Date: Tue, 19 Jan 1999 12:28:57 +0000 This is a multi-part message in MIME format. --------------5759F6A7344AFC8B37562891 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit El Jeffo wrote: > > Gosh, the subscribe to this list was faster than I thought :) > Perhaps you folks can help me out. > > Say I have the following: > > t=[1:.1:10] > x=sin(t) > and I want to plot the derivative of sin(t) (but I want to compute it) > > I tried > y=diff(x) > > and then plot(t,x,t,y) yields me an error message that states the > the vector sizes must be the same.. so I did > plot(t,x,[1.1:.1:10],y) > > and it worked, but the y is really small and never goes beyond .1 in > value. Do you think you could point me in the right direction? > I guess I'm differentiating wrong, how should this really be done? Try the enclose `diffn' Joao > > Thanks :) > > Jeff -- Joao Cardoso | e-mail: jcardoso at inescn dot pt INESC, R. Jose Falcao 110 | tel: + 351 2 2094322 4050 Porto, Portugal | fax: + 351 2 2008487 --------------5759F6A7344AFC8B37562891 Content-Type: application/octet-stream; name="diffn.m" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="diffn.m" ZnVuY3Rpb24gZGF0YWwgPSBkaWZmbihkYXRhLHN0ZXAsb3JkZXIpCgojIGRhdGEgPSBkaWZm bihkYXRhIFssc3RlcCBbLG9yZGVyXV0pCiMKIyBDb21wdXRlcyB0aGUgb3JkZXIgKDw9NCkg Y2VudGVyZWQgZmluaXRlIGRlcml2YXRpdmUgb2YgZGF0YSwgd2l0aCBzdGVwIGR4LgojIFVz ZXMgVGF5bG9yIHNlcmllcyBleHBhbnNpb24gdXAgdG8gdGhlIHNlY29uZCBkZXJpdmF0aXZl LgojIFRoZSBmaXJzdC9sYXN0IHBvaW50cyBhcmUgY29tcHV0ZWQgd2l0aCBmb3J3YXJkL2Jh Y2t3YXJkIGZpbml0ZSBkaWZlcmVuY2VzLgojIFRoZSBzdGVwIGlzIGltcG9ydGFudCBmb3Ig Y29ycmVjdCBzY2FsaW5nLgojIHN0ZXAgYW5kIG9yZGVyIGRlZmF1bHQgdG8gMQoKaWYgKG5h cmdpbiA9PSAxKQoJc3RlcCA9IDE7IG9yZGVyID0gMTsKZWxzZWlmIChuYXJnaW4gPT0gMikK CW9yZGVyID0gMTsKZW5kCgppZiAob3JkZXIgPiA0IHx8IG9yZGVyIDwgMSkKCXVzYWdlKCJv cmRlciBtdXN0IGJlOiAgPD0gMSBvcmRlciA8PSA0ICIpOwplbmRpZgoKaWYgKCEgaXNfdmVj dG9yKGRhdGEpKQoJZXJyb3IoImRpZmZuIG9ubHkgb3BlcmF0ZSBvbiByb3cvY29sdW1uIHZl Y3RvcnMuIEZJWE1FIik7CmVuZGlmCgpbbnIgbmNdPXNpemUoZGF0YSk7Cgpyb3dfZiA9IDA7 CmlmIChuciA+IG5jKQoJZGF0YSA9IGRhdGEnOwoJcm93X2YgPSAxOwplbmRpZjsKCm5fY29s cz1jb2x1bW5zKGRhdGEpOwoKZGF0YWw9emVyb3MoMSxuX2NvbHMpOwoKaWYgKG9yZGVyID09 IDEpCgljb2VmID0gWzE7LTg7MDs4Oy0xXTsgZGl2ID0gMTIqc3RlcDsgd2luID0gMjsJIyBj ZW50ZXJlZCBkaWZmZXJlbmNlCgloX2NvZWYgPSBbLTM7NDstMV07IGhfZGl2ID0gMipzdGVw OyBoX3dpbiA9IDI7CSMgZm9yd2FyZC9iYWNrd2FyZAoJdF9jb2VmID0gLWZsaXB1ZChoX2Nv ZWYpOwplbHNlaWYgKG9yZGVyID09IDIpCgljb2VmID0gWy0xOzE2Oy0zMDsxNjstMV07IGRp diA9IDEyKnN0ZXBeMjsgd2luID0gMjsKCWhfY29lZiA9IFsyOy01OzQ7LTFdOyBoX2RpdiA9 IHN0ZXBeMjsgaF93aW4gPSAzOwoJdF9jb2VmID0gZmxpcHVkKGhfY29lZik7CQplbHNlaWYg KG9yZGVyID09IDMpCgljb2VmID0gWzE7LTg7MTM7MDstMTM7ODstMV07IGRpdiA9IDgqc3Rl cF4zOyB3aW4gPSAzOwoJaF9jb2VmID0gWy01OzE4Oy0yNDsxNDstM107IGhfZGl2ID0gMipz dGVwXjM7IGhfd2luID0gNDsKCXRfY29lZiA9IC1mbGlwdWQoaF9jb2VmKTsJCmVsc2VpZiAo b3JkZXIgPT0gNCkKCWNvZWYgPSBbLTE7MTI7LTM5OzU2Oy0zOTsxMjstMV07IGRpdiA9IDYq c3RlcF40OyB3aW4gPSAzOwoJaF9jb2VmID0gWzM7LTE0OzI2Oy0yNDsxMTstMl07IGhfZGl2 ID0gc3RlcF40OyBoX3dpbiA9IDU7Cgl0X2NvZWYgPSBmbGlwdWQoaF9jb2VmKTsJCmVuZGlm Cgpmb3IgaT13aW4rMTpuX2NvbHMtd2luCglkYXRhbChpKSA9IChkYXRhKGktd2luOmkrd2lu KSAqIGNvZWYpL2RpdjsKZW5kZm9yCgojIGhlYWQ6IHVzZSBmb3J3YXJkIGRpZmVyZW5jZXMg aGVyZQpmb3IgaT0xOndpbgoJZGF0YWwoaSkgPSAoZGF0YShpOmhfd2luK2kpICogaF9jb2Vm KS9oX2RpdjsKIwlkYXRhbChpKSA9IG1lYW4oZGF0YWwod2luKzE6bl9jb2xzLXdpbikpOwpl bmRmb3IKCiMgdGFpbDogYW5kIGJhY2t3YXJkIGRpZmZlcmVuY2VzIGhlcmUKZm9yIGk9bl9j b2xzLXdpbisxOm5fY29scwoJZGF0YWwoaSkgPSAoZGF0YShpLWhfd2luOmkpICogdF9jb2Vm KS9oX2RpdjsKIwlkYXRhbChpKSA9IG1lYW4oZGF0YWwod2luKzE6bl9jb2xzLXdpbikpOwkK ZW5kZm9yCgppZiAocm93X2YpCglkYXRhbCA9IGRhdGFsJzsKZW5kaWYKCmVuZGZ1bmN0aW9u Cg== --------------5759F6A7344AFC8B37562891--