Thalia
Reputation
Next privilege 250 Rep.
 Feb 23 comment Are proofs by contradiction really logical? From all this I understand that the counter-examples only happen when you define the contradiction wrong. If you ask to withdraw 20 dollars, and the bank says they are not there, that does not mean you don't have 20 dollars. The statements "your account at this moment contains 20 dollars" and "your account at this moment does not contain 20 dollars" are contradictory - and only if "this moment" is exactly identical in both statements. Nov 5 comment Find the position difference between two transformations of a line @AaronGolden I don't quite get what you are saying... This is what I understand: If I perform a single transformation (for example translate, rotate, translate back) the pos does not change but the resulting matrix will contain translating coefficients. It is what I use to apply transformations for all objects (with or without scaling). What I need: values to translate the pos so that replacing the old transform with a new transform will leave a point unchanged - a point that is not used as anchor in any of the transforms. Nov 5 comment Find the position difference between two transformations of a line @AaronGolden Interesting suggestion, I am trying to apply reverse transform (I updated my question) - but like with everything I have tried, all points seem to move... A possible cause: the transform I must apply to the object rotates around center, but if I apply transforms to keep P2 (or P1) constant, the shift will be wrong... I just can't find a way to mix them... This may just be one cause of the "wrongness". Also - not quite clear on your statement "scales and rotations fix the origin" - do you mean they can be applied on a different origin ? Oct 15 comment Find a shape that fits inside a box, given it may be drawn with thick pen The top then may be y/cos(theta)' I think Oct 15 comment Find a shape that fits inside a box, given it may be drawn with thick pen So that is something like x=y/tan(arctan(2h/w)/2)` right ? Thanks I will try to figure out a similar formula for the top shift Sep 24 comment Determine shift between scaled rotated object and additional scale step Thank you, I have tried with different permutations of the sign... It's not working... and I can't seem to find a pattern. I was able to make it work by correcting by the difference of the "old" and "new" transforms - as I mentioned in my edit a few hours ago. So perhaps when I have time I can figure out a formula based on initial W and H, previous scale x and y, current scale x and y, and angle. I am certain that without the "old" scales it is impossible to obtain a result... But the matrix difference worked. Sep 24 comment Determine shift between scaled rotated object and additional scale step the scaling factors are different on x and y; the item state "before" is not necessarily with scale (1, 1) - it may have scaling applied just a different scale than the final element. I imagine the height, affected by a scaling factor on y, would just be added... Sep 24 comment Determine shift between scaled rotated object and additional scale step I'll try it, will the vertical offset be based on height change and sin alpha ? does this not depend on the length of the previous object ? Sep 24 comment Determine shift between scaled rotated object and additional scale step Yes something like that - the yellow picture is never an output, but the scaled rotated text is rotated around a scaled text center. Sep 24 comment Determine shift between scaled rotated object and additional scale step I cannot apply separate (intermediate) transformations. To avoid the skew shown in second picture, at any transformation I can only apply a complete transformation matrix, containing all translations, rotations and scales applied from the initial non transformed object. So technically I change a "transformed" object by removing its transform and applying the new transform with either rotation or scaling changed. Sep 24 comment Determine shift between scaled rotated object and additional scale step Assume the input is the green text, and desired output, the blue text Sep 24 comment Determine shift between scaled rotated object and additional scale step All objects start non-scaled non-rotated, there may be an unknown number of transformations applied at any time. Rotation doesn't give me trouble though - it is the scaled of a rotated (and maybe stretched) item that gives problem Sep 24 comment Determine shift between scaled rotated object and additional scale step @Aretino The yellow text shows how the transformation is applied to get between any intermediate position and the final - first scales, then rotates around the center of the scaled item - I only posted to show the center of rotation change. May 5 comment Mean of a practical distribution Sorry I didn't know how to format math expressions - I have only formatted code so far - and I don't have rights to edit other people's posts to see their formatting (too few points). Thank you. May 5 comment Mean of a practical distribution See wikipedia - mean of a probability distribution - expected value: en.wikipedia.org/wiki/Expected_value May 5 comment Mean of a practical distribution Seriously ? You replace pi (probability index i to go along with xi) with π, then tell me it makes no sense and mark it down ? May 2 comment Mean of a practical distribution Used Excel's mean, and noticed that it was wrong.