BBS: Inland Empire Archive Date: 08-13-92 (14:37) Number: 166 From: RICK PEDLEY Refer#: NONE To: JIM VAN NULAND Recvd: NO Subj: 80787 native trig functi Conf: (2) Quik_Bas

On 08-12-92 Jim Van Nuland wrote to All... JV> Math co-processors from the 387 onward have built-in trig JV> functions, which would probably be a hundred times faster JV> than doing the calculations the long way (that is, in JV> 8087 mode). JV> But the Quickbasic library doesn't take advantage of this JV> potential speedup -- optical and astronomical programs JV> are full ofSINandCOScalls. JV> JV> Does anyone know of a replacement trig function library JV> that utilizes the native cabability of the newer math JV> chips? Is Microsoft listening? I don't know of such a library but there are a couple of things you can do to speed up calculations significantly. The first is to pre-calculate and store in an array all the trig values you'll need in the rest of the program. Something like: DERFINT A-ZDIMSine!(360), Cosine!(360) Radians! = 0FORx = 1TO360 Radians! = Radians! + .01744'(6.28 / 360)Sine!(x) = SIN(x) Cosine!(x) = COS(x)NEXTx x = 45'etc.As well, if any portion of a formula remains constant in value (in Circ! = 2 * Pi! * r! for example), its value should be substituted directly, so it'd be Circ! = 6.28 * r! The second speed-up technique is to do calculations using long integers wherever possible, though with astronomical distances you'll easily exceed the +/- ~2 billion range of long integers. With money for example, you'd convert all amounts to cents and store/calculate them as long integers. ... OFFLINE 1.40 --- Maximus 2.01wb * Origin: The BULLpen BBS * Intel 14.4EX (613)549-5168 (1:249/140)

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