FT - Fourier Transform ||

PURPOSE

Computes Fourier transform of a 2D or 3D image, or inverse Fourier transform of a complex Fourier-formatted file.

SEE ALSO

FF	[Fourier Filter]
FP	[Fourier interpolation ||]
FQ	[Filter - Quick Fourier, High, low pass, etc. ||]

USAGE

.OPERATION: FT

.INPUT FILE: H_PIC001
[Enter file name of data to be Fourier-transformed or file name of complex data to be inversely Fourier-transformed.]

.OUTPUT FILE: H_IMG023
[Enter file name which will contain the transformed image.]

NOTES

1. The Fourier transform is stored in a straightforward format. Coefficient (0,0) is placed in location (1,1). The LI operation may be used to list values of a Fourier format file.

2. When SPIDER is linked with the FFTW3 library, multiple threads are used (if supported by the current SET MP setting).

3. On SGI systems equipped with SGI's LIBFFT library, or when SPIDER is linked with the FFTW library, this operation (and other SPIDER Fourier operations) works for all possible dimensions. For dimensions that are large prime numbers or products of large prime numbers it may be slow.
   

4. When using SPIDER's local FFT code Fourier operations DO NOT work for the following dimensions:
   29 31 37 41 43 47 53 58 59 61 62 67 71 73 74 79 82 83 86 87 89 93 94 97 101 103 106 107 109 111 113 116 118 122 123 124 127 129 131 134 137 139 141 142 145 146 148 149 151 155 157 158 159 163 164 166 167 172 173 174 177 178 179 181 183 185 186 188 191 193 194 197 199 201 202 203 205 206 211 212 213 214 215 217 218 219 221 222 223 226 227 229 230 231 232 233 235 236 237 238 239 241 244 246 247 248 249 251 253 254 255 257 258 259 261 262 263 265 266 267 268 269 271 273 274 277 278 279 281 282 283 284 285 286 287 290 291 292 293 295 296 298 299 301 302 303 305 307 309 310 311 313 314 316 317 318 319 321 322 323 326 327 328 329 330 331 332 333 334 335 337 339 341 344 345 346 347 348 349 353 354 355 356 357 358 359 362 365 366 367 369 370 371 372 373 374 376 377 379 381 382 383 385 386 387 388 389 390 391 393 394 395 397 398 399 401 402 403 404 406 407 409 410 411 412 413 415 417 418 419 421 422 423 424 426 427 428 429 430 431 433 434 435 436 437 438 439 442 443 444 445 446 447 449 451 452 453 454 455 457 458 461 462 463 464 465 466 467 469 470 471 472 473 474 477 478 479 481 482 483 485 487 488 489 491 492 493 494 496 497 498 499 501 502 503 505 506 508 509 510 511 514 515 516 517 518 519 521 522 523 524 526 527 530 531 533 534 535 536 537 538 541 542 543 545 546 547 548 549 551 553 554 555 556 557 558 559 561 562 563 564 565 566 568 569 570 571 573 574 577 579 580 581 582 583 584 586 587 589 590 591 592 593 595 596 597 598 599 601 602 603 604 606 607 609 610 611 613 614 615 617 618 619 620 622 623 626 627 628 629 631 632 633 634 635 636 638 639 641 642 643 645 646 647 649 651 652 653 654 655 656 657 658 659 661 662 663 664 665 666 667 668 669 670 671 673 674 677 678 679 681 682 683 685 687 688 689 690 691 692 694 695 696 697 698 699 701 703 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 721 723 724 725 727 730 731 732 733 734 737 738 739 740 741 742 743 744 745 746 747 749 751 752 753 754 755 757 758 759 761 762 763 764 766 767 769 770 771 772 773 774 775 776 777 778 779 781 782 783 785 786 787 788 789 790 791 793 794 795 796 797 798 799 801 802 803 804 805 806 807 808 809 811 812 813 814 815 817 818 820 821 822 823 824 826 827 829 830 831 834 835 837 838 839 841 842 843 844 846 848 849 851 852 853 854 856 857 858 859 860 861 862 863 865 866 868 869 870 871 872 873 874 876 877 878 879 881 883 884 885 886 887 888 889 890 892 893 894 895 897 898 899 901 902 903 904 905 906 907 908 909 910 911 913 914 915 916 917 919 920 921 922 923 924 925 926 927 928 929 930 932 933 934 935 937 938 939 940 941 942 943 944 946 947 948 949 951 952 953 954 955 956 957 958 959 961 962 963 964 965 966 967 969 970 971 973 974 976 977 978 979 981 982 983 984 985 986 987 988 989 991 992 993 994 995 996 997 998 999 1001 1002 1003 1004 1005 1006 1007 1009 1010 1011 1012 1013 1015 1016 1017 1018 1019 1020 1021 1022 1023
   (and so on....)

5. Implemented by P. Penczek.

SUBROUTINES

FFTMCF, FMRS_1, FMRS_2R, FMRS_3R, FMRS_FFTW3, FMRS_2, FMRS_2DR, FMRS_3, FMRS_3DR

CALLER

FOUR1 , FOUR1C