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Annotation of OpenXM_contrib/PHC/Ada/Schubert/chebychev_polynomials.adb, Revision 1.1

1.1     ! maekawa     1: with Standard_Mathematical_Functions;    use Standard_Mathematical_Functions;
        !             2:
        !             3: package body Chebychev_Polynomials is
        !             4:
        !             5:   function Create ( k : natural ) return Vector is
        !             6:   begin
        !             7:     if k = 0
        !             8:      then declare
        !             9:             res : Vector(0..0);
        !            10:           begin
        !            11:             res(0) := 1.0;
        !            12:             return res;
        !            13:           end;
        !            14:      elsif k = 1
        !            15:          then declare
        !            16:                 res : Vector(0..1);
        !            17:               begin
        !            18:                 res(0) := 0.0;
        !            19:                 res(1) := 1.0;
        !            20:                 return res;
        !            21:               end;
        !            22:          else declare
        !            23:                 res : Vector(0..k);
        !            24:                 tk1 : constant Vector := Create(k-1);
        !            25:                 tk2 : constant Vector := Create(k-2);
        !            26:               begin
        !            27:                 for i in tk1'range loop
        !            28:                   res(i+1) := 2.0*tk1(i);
        !            29:                 end loop;
        !            30:                 res(0) := 0.0;
        !            31:                 for i in tk2'range loop
        !            32:                   res(i) := res(i) - tk2(i);
        !            33:                 end loop;
        !            34:                 return res;
        !            35:               end;
        !            36:     end if;
        !            37:   end Create;
        !            38:
        !            39:   function Eval ( k : natural; x : double_float ) return double_float is
        !            40:
        !            41:     res : double_float := COS(double_float(k)*ARCCOS(x));
        !            42:
        !            43:   begin
        !            44:     return res;
        !            45:   end Eval;
        !            46:
        !            47:   function Eval ( p : Vector; x : double_float ) return double_float is
        !            48:
        !            49:     res : double_float := p(0);
        !            50:     pow : double_float := x;
        !            51:
        !            52:   begin
        !            53:     for i in 1..p'last loop
        !            54:       res := res + p(i)*pow;
        !            55:       pow := pow*x;
        !            56:     end loop;
        !            57:     return res;
        !            58:   end Eval;
        !            59:
        !            60:   function Diff ( p : Vector ) return Vector is
        !            61:
        !            62:     res : Vector(0..p'last-1);
        !            63:
        !            64:   begin
        !            65:     for i in res'range loop
        !            66:       res(i) := double_float(i+1)*p(i+1);
        !            67:     end loop;
        !            68:     return res;
        !            69:   end Diff;
        !            70:
        !            71:   function Diff ( p : Vector; k : natural ) return Vector is
        !            72:   begin
        !            73:     if k = 0
        !            74:      then return p;
        !            75:      elsif k = 1
        !            76:          then return Diff(p);
        !            77:          else return Diff(Diff(p),k-1);
        !            78:        end if;
        !            79:   end Diff;
        !            80:
        !            81:   function Int ( p : Vector ) return Vector is
        !            82:
        !            83:     res : Vector(0..p'last+1);
        !            84:
        !            85:   begin
        !            86:     res(0) := 0.0;
        !            87:     for i in p'range loop
        !            88:       res(i+1) := p(i)/double_float(i+1);
        !            89:     end loop;
        !            90:     return res;
        !            91:   end Int;
        !            92:
        !            93:   function Int ( p : Vector; k : natural ) return Vector is
        !            94:   begin
        !            95:     if k = 0
        !            96:      then return p;
        !            97:      elsif k = 1
        !            98:          then return Int(p);
        !            99:          else return Int(Int(p),k-1);
        !           100:     end if;
        !           101:   end Int;
        !           102:
        !           103: end Chebychev_Polynomials;