Changeset 2cdfc8 in git
- Timestamp:
- Mar 22, 2011, 10:33:58 AM (12 years ago)
- Branches:
- (u'jengelh-datetime', 'ceac47cbc86fe4a15902392bdbb9bd2ae0ea02c6')(u'spielwiese', 'a800fe4b3e9d37a38c5a10cc0ae9dfa0c15a4ee6')
- Children:
- 21ee926ee8ae7b87879f1075406bc488cb810470
- Parents:
- a41cdb0b52788c0c83732f7ac9d14650d4908bfd
- File:
-
- 1 edited
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Singular/LIB/paraplanecurves.lib
ra41cdb r2cdfc8 228 228 /////////////////////////////////////////////////////////////////////////////// 229 229 proc paraPlaneCurve(poly f, list #) 230 "USAGE: paraPlaneCurve(f [, c]); f poly , c optional integer@*231 optional integer ccan be: @*232 1: compute integral basis via normalization. @*233 2: make local analysis of singularities first and apply normalization234 separately. @*230 "USAGE: paraPlaneCurve(f [, s]); f poly , s optional string@* 231 optional string s can be: @* 232 'normal': compute integral basis via normalization. @* 233 'local': make local analysis of singularities first and apply 234 normalization separately. @* 235 235 The default is 2. @* 236 236 ASSUME: The basering must be a polynomial ring in three variables, say x,y,z, … … 240 240 (see @ref{genus}). @* 241 241 These conditions will be checked automatically. 242 RETURN: ring with an ideal PARA. 242 RETURN: ring with an ideal PARA which contains a rational parametrization of 243 the rational plane curve given by f; the ground field of the returned 244 polynomial ring is either Q or some algebraic extension Q(a); PARA 245 consists of three generators that parametrize the three coordinates 246 of the rational curve 243 247 THEORY: After a first step, realized by a projective automorphism in the 244 248 procedure adjointIdeal, C satisfies: @* … … 272 276 " 273 277 { 274 if(size(#)==0) {int choice = 2;} else {int choice = #[1];} 278 int choice = 2; 279 if (size(#) != 0) 280 { 281 if (typeof(#[1]) == "string") 282 { 283 string s = string(#[1]); 284 if (s == "normal") { choice = 1; } 285 else 286 { 287 if (s == "local") { choice = 2; } 288 else { ERROR("expected optional argument to be either" 289 + " 'local' or 'normal'"); } 290 } 291 } 292 else { ERROR("expected optional argument to be a string"); } 293 } 275 294 def Roriginal = basering; 276 295 /*checking assumptions and handling the conic case*/
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