user: What would the C source look like for the assembly code provided here:

```asm
<main>:
  endbr64
  push   %r15
  mov    $0x14,%esi
  mov    $0x1,%edi
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0xc8,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0xb8(%rsp)
  xor    %eax,%eax
  call   <ivector@plt>
  mov    $0x14,%esi
  mov    $0x1,%edi
  mov    %rax,0x30(%rsp)
  call   <ivector@plt>
  mov    $0x14,%ecx
  mov    $0x1,%edx
  mov    $0x14,%esi
  mov    $0x1,%edi
  mov    %rax,0x20(%rsp)
  call   <matrix@plt>
  mov    $0x14,%ecx
  mov    $0x1,%edx
  mov    $0x14,%esi
  mov    $0x1,%edi
  mov    %rax,0x10(%rsp)
  call   <matrix@plt>
  mov    $0x14,%ecx
  mov    $0x1,%edx
  mov    $0x14,%esi
  mov    $0x1,%edi
  mov    %rax,0x18(%rsp)
  call   <matrix@plt>
  mov    $0x14,%ecx
  mov    $0x1,%edx
  mov    $0x14,%esi
  mov    $0x1,%edi
  mov    %rax,%r15
  call   <matrix@plt>
  lea    D49(%rip),%rsi
  lea    D42(%rip),%rdi
  mov    %rax,0x38(%rsp)
  call   <fopen@plt>
  mov    %rax,0x28(%rsp)
  test   %rax,%rax
  je     L489
L622:
  mov    0x28(%rsp),%rdi
  mov    0x38(%rsp),%rbp
  mov    %r15,%r12
  call   <feof@plt>
  test   %eax,%eax
  jne    L565
L619:
  mov    0x28(%rsp),%r14
  lea    0x60(%rsp),%rbx
  mov    $0x50,%esi
  mov    $0x1,%r15d
  mov    %rbx,%rdi
  mov    %rbx,0x8(%rsp)
  lea    D173(%rip),%r13
  mov    %r14,%rdx
  call   <fgets@plt>
  mov    %rbx,%rdi
  mov    %r14,%rdx
  mov    $0x50,%esi
  call   <fgets@plt>
  lea    0x54(%rsp),%rcx
  mov    %r14,%rdi
  xor    %eax,%eax
  lea    0x58(%rsp),%rdx
  lea    D183(%rip),%rsi
  call   <fscanf@plt>
  mov    %rbx,%rdi
  mov    %r14,%rdx
  mov    $0x50,%esi
  call   <fgets@plt>
  mov    0x10(%rsp),%rax
  mov    0x58(%rsp),%edi
  lea    0x8(%rax),%rbx
  test   %edi,%edi
  jle    L94
  mov    %r12,0x40(%rsp)
  mov    %rbp,0x48(%rsp)
  nopl   0x0(%rax,%rax,1)
L330:
  mov    $0x4,%r12d
  mov    $0x1,%ebp
  nopl   0x0(%rax,%rax,1)
L346:
  mov    (%rbx),%rdx
  mov    %r13,%rsi
  mov    %r14,%rdi
  xor    %eax,%eax
  add    $0x1,%ebp
  add    %r12,%rdx
  add    $0x4,%r12
  call   <fscanf@plt>
  mov    0x58(%rsp),%eax
  cmp    %ebp,%eax
  jge    L346
  add    $0x1,%r15d
  cmp    %r15d,%eax
  jl     L475
  add    $0x8,%rbx
  jmp    L330
L475:
  mov    0x40(%rsp),%r12
  mov    0x48(%rsp),%rbp
L94:
  mov    0x28(%rsp),%rbx
  mov    0x8(%rsp),%rdi
  mov    $0x50,%esi
  mov    %rbx,%rdx
  call   <fgets@plt>
  mov    0x54(%rsp),%esi
  test   %esi,%esi
  jle    L673
  mov    0x58(%rsp),%eax
  mov    %r12,0x40(%rsp)
  xor    %r14d,%r14d
  lea    D173(%rip),%r13
  mov    %rbx,%r12
  test   %eax,%eax
  jle    L140
  nopl   0x0(%rax)
L532:
  lea    0x1(%r14),%rax
  mov    $0x1,%r15d
  mov    %rax,0x8(%rsp)
  lea    0x0(,%rax,4),%rbx
  nopw   0x0(%rax,%rax,1)
L55:
  mov    0x0(%rbp,%r15,8),%rdx
  mov    %r13,%rsi
  mov    %r12,%rdi
  xor    %eax,%eax
  add    $0x1,%r15
  add    %rbx,%rdx
  call   <fscanf@plt>
  mov    0x58(%rsp),%eax
  cmp    %r15d,%eax
  jge    L55
  add    $0x2,%r14d
  cmp    0x54(%rsp),%r14d
  jg     L140
  mov    0x8(%rsp),%r14
  test   %eax,%eax
  jg     L532
L140:
  mov    0x40(%rsp),%r12
L673:
  lea    D25(%rip),%rdi
  call   <puts@plt>
  mov    0x58(%rsp),%esi
  test   %esi,%esi
  jle    L404
  mov    0x10(%rsp),%rax
  mov    $0x1,%r15d
  lea    D63(%rip),%rbx
  lea    0x8(%rax),%r14
  nopl   (%rax)
L534:
  xor    %eax,%eax
  nopw   0x0(%rax,%rax,1)
L626:
  mov    (%r14),%rdx
  pxor   %xmm0,%xmm0
  lea    0x1(%rax),%r13
  mov    %rbx,%rdi
  cvtss2sd 0x4(%rdx,%rax,4),%xmm0
  mov    $0x1,%eax
  call   <printf@plt>
  mov    %r13,%rax
  lea    0x1(%r13),%edx
  cmp    %edx,0x58(%rsp)
  jge    L626
  mov    $0xa,%edi
  add    $0x1,%r15d
  add    $0x8,%r14
  call   <putchar@plt>
  mov    0x58(%rsp),%esi
  cmp    %r15d,%esi
  jge    L534
L404:
  mov    0x30(%rsp),%rdx
  mov    0x10(%rsp),%rdi
  lea    0x5c(%rsp),%rcx
  call   <ludcmp@plt>
  mov    0x58(%rsp),%r15d
  mov    $0x1,%r8d
  lea    0x1(%r15),%eax
  mov    %rax,0x8(%rsp)
  test   %r15d,%r15d
  jle    L263
  mov    %rbp,0x40(%rsp)
  movss  D142(%rip),%xmm7
  pxor   %xmm6,%xmm6
  nopl   0x0(%rax,%rax,1)
L41:
  mov    0x10(%rsp),%rax
  mov    (%r12,%r8,8),%rdx
  cmp    %r8d,%r15d
  mov    %r8d,%edi
  cmovle %r15d,%edi
  mov    %r8d,%r10d
  mov    (%rax,%r8,8),%rcx
  mov    0x18(%rsp),%rax
  lea    0x14(%rdx),%rbx
  mov    (%rax,%r8,8),%rsi
  lea    0x14(%rcx),%r11
  lea    0x4(%rdx),%rax
  cmp    %rax,%r11
  lea    0x4(%rcx),%r11
  setbe  %al
  cmp    %r11,%rbx
  lea    0x4(%rsi),%r9
  setbe  %r11b
  lea    0x8(%rcx),%rbx
  or     %r11d,%eax
  cmp    $0x3,%edi
  setg   %r11b
  and    %r11d,%eax
  mov    %r9,%r11
  sub    %rbx,%r11
  cmp    $0x8,%r11
  seta   %r11b
  test   %r11b,%al
  je     L292
  lea    0x8(%rdx),%rax
  sub    %rax,%r9
  cmp    $0x8,%r9
  jbe    L292
  test   %edi,%edi
  mov    $0x1,%r9d
  movd   %r8d,%xmm4
  cmovg  %edi,%r9d
  pshufd $0x0,%xmm4,%xmm5
  movdqa D92(%rip),%xmm4
  mov    %r9d,%eax
  shr    $0x2,%eax
  lea    -0x1(%rax),%r11d
  mov    $0x4,%eax
  shl    $0x4,%r11
  add    $0x14,%r11
  nopw   0x0(%rax,%rax,1)
L560:
  movdqa %xmm4,%xmm3
  movdqa %xmm5,%xmm0
  movups (%rdx,%rax,1),%xmm1
  paddd  D196(%rip),%xmm4
  pcmpgtd %xmm3,%xmm0
  paddd  D179(%rip),%xmm3
  movdqa %xmm0,%xmm2
  pcmpeqd %xmm6,%xmm2
  andps  %xmm2,%xmm1
  movups %xmm1,(%rdx,%rax,1)
  movups (%rcx,%rax,1),%xmm1
  andps  %xmm1,%xmm2
  andps  %xmm0,%xmm1
  andnps D142(%rip),%xmm0
  movups %xmm2,(%rdx,%rax,1)
  orps   %xmm1,%xmm0
  movups %xmm0,(%rsi,%rax,1)
  add    $0x10,%rax
  cmp    %rax,%r11
  jne    L560
  mov    %r9d,%r11d
  pshufd $0xff,%xmm3,%xmm3
  and    $0xfffffffc,%r11d
  movd   %xmm3,%eax
  lea    0x1(%r11),%ebx
  cmp    %r11d,%r9d
  je     L501
  movslq %ebx,%r9
  shl    $0x2,%r9
  lea    (%rcx,%r9,1),%r13
  lea    (%rdx,%r9,1),%rbp
  lea    (%rsi,%r9,1),%rax
  cmp    %ebx,%r10d
  jle    L392
  movl   $0x0,0x0(%rbp)
  movss  0x0(%r13),%xmm0
L9:
  movss  %xmm0,(%rax)
  lea    0x2(%r11),%eax
  cmp    %eax,%edi
  jl     L501
  lea    0x4(%r9),%rbx
  lea    (%rcx,%rbx,1),%r13
  lea    (%rdx,%rbx,1),%rbp
  add    %rsi,%rbx
  cmp    %eax,%r10d
  jle    L491
  movl   $0x0,0x0(%rbp)
  movss  0x0(%r13),%xmm0
L254:
  lea    0x3(%r11),%eax
  movss  %xmm0,(%rbx)
  cmp    %edi,%eax
  jg     L501
  add    $0x8,%r9
  lea    (%rcx,%r9,1),%rdi
  lea    (%rdx,%r9,1),%rbx
  add    %rsi,%r9
  cmp    %eax,%r10d
  jle    L390
  movl   $0x0,(%rbx)
  movss  (%rdi),%xmm0
L633:
  movss  %xmm0,(%r9)
  lea    0x4(%r11),%eax
L501:
  cmp    %eax,%r15d
  jl     L182
  movslq %eax,%rdi
  lea    0x0(,%rdi,4),%r9
  lea    0x4(%r9),%rbx
  lea    (%rsi,%r9,1),%r10
  lea    (%rcx,%rbx,1),%rbp
  mov    %r10,%r13
  lea    (%rdx,%r9,1),%r11
  sub    %rbp,%r13
  mov    %r11,%r14
  cmp    $0x8,%r13
  seta   %r13b
  sub    %rbp,%r14
  cmp    $0x8,%r14
  seta   %bpl
  and    %r13d,%ebp
  cmp    %eax,%r15d
  setg   %r13b
  test   %r13b,%bpl
  je     L374
  add    %rdx,%rbx
  mov    %r10,%rbp
  sub    %rbx,%rbp
  cmp    $0x8,%rbp
  jbe    L374
  mov    %r15d,%ebx
  sub    %eax,%ebx
  lea    0x1(%rbx),%ebp
  cmp    $0x2,%ebx
  jbe    L427
  mov    %ebp,%r13d
  add    %rcx,%r9
  pxor   %xmm0,%xmm0
  xor    %ebx,%ebx
  shr    $0x2,%r13d
  shl    $0x4,%r13
  nopl   (%rax)
L0:
  movups (%r9,%rbx,1),%xmm5
  movups %xmm5,(%r11,%rbx,1)
  movups %xmm0,(%r10,%rbx,1)
  add    $0x10,%rbx
  cmp    %r13,%rbx
  jne    L0
  mov    %ebp,%r9d
  and    $0xfffffffc,%r9d
  add    %r9d,%eax
  cmp    %ebp,%r9d
  je     L182
L218:
  sub    %r9d,%ebp
  cmp    $0x1,%ebp
  je     L195
  add    %r9,%rdi
  mov    (%rcx,%rdi,4),%r9
  mov    %r9,(%rdx,%rdi,4)
  movq   $0x0,(%rsi,%rdi,4)
  mov    %ebp,%edi
  and    $0xfffffffe,%edi
  add    %edi,%eax
  cmp    %ebp,%edi
  je     L182
L195:
  cltq
  movss  (%rcx,%rax,4),%xmm0
  movss  %xmm0,(%rdx,%rax,4)
  movl   $0x0,(%rsi,%rax,4)
L182:
  add    $0x1,%r8
  cmp    0x8(%rsp),%r8
  jne    L41
  mov    0x40(%rsp),%rbp
  mov    0x20(%rsp),%r11
  mov    $0x1,%ebx
  pxor   %xmm2,%xmm2
  mov    0x18(%rsp),%r13
  mov    $0x4,%r14d
  nopl   (%rax)
L160:
  mov    %ebx,(%r11,%rbx,4)
  mov    0x58(%rsp),%r10d
  test   %r10d,%r10d
  jle    L263
  mov    0x0(%rbp,%rbx,8),%rdx
  mov    %r10d,%eax
  mov    %r14,%r8
  mov    0x0(%r13,%rbx,8),%rdi
  lea    0x1(%r10),%esi
  lea    (%rdx,%rax,4),%r9
  sub    %rdx,%r8
  nopl   0x0(%rax)
L632:
  movl   $0x0,0x4(%rdx)
  lea    (%r8,%rdx,1),%rcx
  mov    $0x1,%eax
  movaps %xmm2,%xmm1
  nopl   0x0(%rax,%rax,1)
L543:
  mov    (%r12,%rax,8),%r15
  movss  (%r15,%rcx,1),%xmm0
  mulss  (%rdi,%rax,4),%xmm0
  add    $0x1,%rax
  addss  %xmm0,%xmm1
  movss  %xmm1,0x4(%rdx)
  cmp    %rax,%rsi
  jne    L543
  add    $0x4,%rdx
  cmp    %rdx,%r9
  jne    L632
  add    $0x1,%rbx
  cmp    %ebx,%r10d
  jge    L160
L263:
  lea    D220(%rip),%rdx
  lea    D57(%rip),%rsi
  xor    %eax,%eax
  lea    D154(%rip),%rdi
  call   <printf@plt>
  mov    0x58(%rsp),%ecx
  mov    $0x1,%eax
  test   %ecx,%ecx
  jle    L286
  mov    0x30(%rsp),%r8
  mov    0x20(%rsp),%rcx
  nopw   0x0(%rax,%rax,1)
L576:
  movslq (%r8,%rax,4),%rdx
  mov    (%rcx,%rax,4),%edi
  lea    (%rcx,%rdx,4),%rdx
  mov    (%rdx),%esi
  mov    %edi,(%rdx)
  mov    %esi,(%rcx,%rax,4)
  mov    0x58(%rsp),%edx
  add    $0x1,%rax
  cmp    %eax,%edx
  jge    L576
  test   %edx,%edx
  jle    L286
  mov    %r12,0x8(%rsp)
  mov    0x20(%rsp),%r15
  mov    $0x1,%r13d
  lea    D63(%rip),%r14
  nopl   (%rax)
L548:
  mov    $0x1,%r12d
  jmp    L166
  nopl   0x0(%rax,%rax,1)
L80:
  add    $0x1,%r12
  cmp    %r12d,%edx
  jl     L536
L166:
  cmp    (%r15,%r12,4),%r13d
  jne    L80
  xor    %eax,%eax
  test   %edx,%edx
  jle    L88
  nopl   (%rax)
L555:
  mov    0x0(%rbp,%r12,8),%rdx
  pxor   %xmm0,%xmm0
  lea    0x1(%rax),%rbx
  mov    %r14,%rdi
  cvtss2sd 0x4(%rdx,%rax,4),%xmm0
  mov    $0x1,%eax
  call   <printf@plt>
  mov    %rbx,%rax
  lea    0x1(%rbx),%edx
  cmp    %edx,0x58(%rsp)
  jge    L555
L88:
  mov    $0xa,%edi
  add    $0x1,%r12
  call   <putchar@plt>
  mov    0x58(%rsp),%edx
  cmp    %r12d,%edx
  jge    L166
  nopl   0x0(%rax,%rax,1)
L536:
  add    $0x1,%r13d
  cmp    %edx,%r13d
  jg     L10
  test   %edx,%edx
  jg     L548
L10:
  mov    0x8(%rsp),%r12
L286:
  lea    D110(%rip),%rdi
  call   <puts@plt>
  mov    0x58(%rsp),%edx
  test   %edx,%edx
  jle    L50
  mov    0x18(%rsp),%rax
  mov    $0x1,%r15d
  lea    D63(%rip),%rbx
  lea    0x8(%rax),%r14
  nopl   0x0(%rax)
L367:
  xor    %eax,%eax
  nopw   0x0(%rax,%rax,1)
L451:
  mov    (%r14),%rdx
  pxor   %xmm0,%xmm0
  lea    0x1(%rax),%r13
  mov    %rbx,%rdi
  cvtss2sd 0x4(%rdx,%rax,4),%xmm0
  mov    $0x1,%eax
  call   <printf@plt>
  mov    %r13,%rax
  lea    0x1(%r13),%edx
  cmp    %edx,0x58(%rsp)
  jge    L451
  mov    $0xa,%edi
  add    $0x1,%r15d
  add    $0x8,%r14
  call   <putchar@plt>
  cmp    %r15d,0x58(%rsp)
  jge    L367
L50:
  lea    D30(%rip),%rdi
  call   <puts@plt>
  mov    0x58(%rsp),%eax
  test   %eax,%eax
  jle    L533
  lea    0x8(%r12),%r14
  mov    $0x1,%r15d
  lea    D63(%rip),%rbx
  nopw   0x0(%rax,%rax,1)
L468:
  xor    %eax,%eax
  nopw   0x0(%rax,%rax,1)
L171:
  mov    (%r14),%rdx
  pxor   %xmm0,%xmm0
  lea    0x1(%rax),%r13
  mov    %rbx,%rdi
  cvtss2sd 0x4(%rdx,%rax,4),%xmm0
  mov    $0x1,%eax
  call   <printf@plt>
  mov    %r13,%rax
  lea    0x1(%r13),%edx
  cmp    %edx,0x58(%rsp)
  jge    L171
  mov    $0xa,%edi
  add    $0x1,%r15d
  add    $0x8,%r14
  call   <putchar@plt>
  cmp    %r15d,0x58(%rsp)
  jge    L468
L533:
  lea    D64(%rip),%rdi
  call   <puts@plt>
  lea    D69(%rip),%rdi
  call   <puts@plt>
  xor    %eax,%eax
  call   <getchar@plt>
  mov    0x28(%rsp),%rdi
  call   <feof@plt>
  test   %eax,%eax
  je     L619
L565:
  mov    0x28(%rsp),%rdi
  call   <fclose@plt>
  mov    0x38(%rsp),%rdi
  mov    $0x14,%r8d
  mov    $0x1,%ecx
  mov    $0x14,%edx
  mov    $0x1,%esi
  call   <free_matrix@plt>
  mov    $0x14,%r8d
  mov    $0x1,%ecx
  mov    %r12,%rdi
  mov    $0x14,%edx
  mov    $0x1,%esi
  call   <free_matrix@plt>
  mov    0x18(%rsp),%rdi
  mov    $0x14,%r8d
  mov    $0x1,%ecx
  mov    $0x14,%edx
  mov    $0x1,%esi
  call   <free_matrix@plt>
  mov    0x10(%rsp),%rdi
  mov    $0x14,%r8d
  mov    $0x1,%ecx
  mov    $0x14,%edx
  mov    $0x1,%esi
  call   <free_matrix@plt>
  mov    0x20(%rsp),%rdi
  mov    $0x14,%edx
  mov    $0x1,%esi
  call   <free_ivector@plt>
  mov    0x30(%rsp),%rdi
  mov    $0x14,%edx
  mov    $0x1,%esi
  call   <free_ivector@plt>
  mov    0xb8(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L337
  add    $0xc8,%rsp
  xor    %eax,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L374:
  movss  (%rcx,%rdi,4),%xmm0
  movss  %xmm0,(%rdx,%rdi,4)
  movl   $0x0,(%rsi,%rdi,4)
  add    $0x1,%rdi
  cmp    %edi,%r15d
  jge    L374
  jmp    L182
L292:
  mov    $0x1,%r9d
  nopl   (%rax)
L243:
  cmp    %r9d,%r10d
  jg     L502
L450:
  movss  (%rcx,%r9,4),%xmm0
  lea    0x1(%r9),%eax
  movss  %xmm0,(%rdx,%r9,4)
  movss  %xmm7,(%rsi,%r9,4)
  add    $0x1,%r9
  cmp    %r9d,%edi
  jl     L501
  cmp    %r9d,%r10d
  jle    L450
L502:
  movl   $0x0,(%rdx,%r9,4)
  movss  (%rcx,%r9,4),%xmm0
  lea    0x1(%r9),%eax
  movss  %xmm0,(%rsi,%r9,4)
  add    $0x1,%r9
  cmp    %r9d,%edi
  jge    L243
  jmp    L501
L392:
  movss  0x0(%r13),%xmm0
  movss  %xmm0,0x0(%rbp)
  movaps %xmm7,%xmm0
  jmp    L9
L491:
  movss  0x0(%r13),%xmm0
  movss  %xmm0,0x0(%rbp)
  movaps %xmm7,%xmm0
  jmp    L254
L390:
  movss  (%rdi),%xmm0
  movss  %xmm0,(%rbx)
  movaps %xmm7,%xmm0
  jmp    L633
L427:
  xor    %r9d,%r9d
  jmp    L218
L489:
  lea    D13(%rip),%rdi
  call   <nrerror@plt>
  jmp    L622
L337:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: read_data
arguments: data_label: D49
data_type: string
name: read_data
arguments: data_label: D42
data_type: string
name: read_data
arguments: data_label: D173
data_type: string
name: read_data
arguments: data_label: D183
data_type: string
name: read_data
arguments: data_label: D25
data_type: string
name: read_data
arguments: data_label: D63
data_type: string
name: read_data
arguments: data_label: D142
data_type: f32[4]
name: read_data
arguments: data_label: D92
data_type: byte[16]
name: read_data
arguments: data_label: D196
data_type: byte[16]
name: read_data
arguments: data_label: D179
data_type: byte[16]
name: read_data
arguments: data_label: D220
data_type: string
name: read_data
arguments: data_label: D57
data_type: string
name: read_data
arguments: data_label: D154
data_type: string
name: read_data
arguments: data_label: D110
data_type: string
name: read_data
arguments: data_label: D30
data_type: string
name: read_data
arguments: data_label: D64
data_type: string
name: read_data
arguments: data_label: D69
data_type: string
name: read_data
arguments: data_label: D13
data_type: string

tool: D49: r

tool: D42: matrx1.dat

tool: D173: %f 

tool: D183: %d %d 

tool: D25: original matrix:

tool: D63: %12.6f

tool: {"D142": [1.0,1.0,1.0,1.0]}

tool: {"D92": [0x01,0x00,0x00,0x00,0x02,0x00,0x00,0x00,0x03,0x00,0x00,0x00,0x04,0x00,0x00,0x00]}

tool: {"D196": [0x04,0x00,0x00,0x00,0x04,0x00,0x00,0x00,0x04,0x00,0x00,0x00,0x04,0x00,0x00,0x00]}

tool: {"D179": [0x01,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x01,0x00,0x00,0x00]}

tool: D220: matrices (rows unscrambled):

tool: D57: product of lower and upper 

tool: D154: 
%s%s


tool: D110: 
lower matrix of the decomposition:

tool: D30: 
upper matrix of the decomposition:

tool: D64: 
***********************************

tool: D69: press return for next problem:

tool: D13: Data file matrx1.dat not found


assistant: ```c
int main(void) {
  int j, k, l, m, n, dum, *indx, *jndx;
  float d, **a, **xl, **xu, **x;
  char dummy[80];
  FILE *fp;
  indx = ivector(1, 20);
  jndx = ivector(1, 20);
  a = matrix(1, 20, 1, 20);
  xl = matrix(1, 20, 1, 20);
  xu = matrix(1, 20, 1, 20);
  x = matrix(1, 20, 1, 20);
  if ((fp = fopen("matrx1.dat", "r")) == NULL)
    nrerror("Data file matrx1.dat not found\n");
  while (!feof(fp)) {
    fgets(dummy, 80, fp);
    fgets(dummy, 80, fp);
    fscanf(fp, "%d %d ", &n, &m);
    fgets(dummy, 80, fp);
    for (k = 1; k <= n; k++)
      for (l = 1; l <= n; l++)
        fscanf(fp, "%f ", &a[k][l]);
    fgets(dummy, 80, fp);
    for (l = 1; l <= m; l++)
      for (k = 1; k <= n; k++)
        fscanf(fp, "%f ", &x[k][l]);
    printf("original matrix:\n");
    for (k = 1; k <= n; k++) {
      for (l = 1; l <= n; l++)
        printf("%12.6f", a[k][l]);
      printf("\n");
    }
    ludcmp(a, n, indx, &d);
    for (k = 1; k <= n; k++) {
      for (l = 1; l <= n; l++) {
        if (l > k) {
          xu[k][l] = a[k][l];
          xl[k][l] = 0.0;
        } else if (l < k) {
          xu[k][l] = 0.0;
          xl[k][l] = a[k][l];
        } else {
          xu[k][l] = a[k][l];
          xl[k][l] = 1.0;
        }
      }
    }
    for (k = 1; k <= n; k++) {
      jndx[k] = k;
      for (l = 1; l <= n; l++) {
        x[k][l] = 0.0;
        for (j = 1; j <= n; j++)
          x[k][l] += (xl[k][j] * xu[j][l]);
      }
    }
    printf("\n%s%s\n", "product of lower and upper ", "matrices (rows unscrambled):");
    for (k = 1; k <= n; k++) {
      dum = jndx[indx[k]];
      jndx[indx[k]] = jndx[k];
      jndx[k] = dum;
    }
    for (k = 1; k <= n; k++)
      for (j = 1; j <= n; j++)
        if (jndx[j] == k) {
          for (l = 1; l <= n; l++)
            printf("%12.6f", x[j][l]);
          printf("\n");
        }
    printf("\nlower matrix of the decomposition:\n");
    for (k = 1; k <= n; k++) {
      for (l = 1; l <= n; l++)
        printf("%12.6f", xl[k][l]);
      printf("\n");
    }
    printf("\nupper matrix of the decomposition:\n");
    for (k = 1; k <= n; k++) {
      for (l = 1; l <= n; l++)
        printf("%12.6f", xu[k][l]);
      printf("\n");
    }
    printf("\n***********************************\n");
    printf("press return for next problem:\n");
    (void)getchar();
  }
  fclose(fp);
  free_matrix(x, 1, 20, 1, 20);
  free_matrix(xu, 1, 20, 1, 20);
  free_matrix(xl, 1, 20, 1, 20);
  free_matrix(a, 1, 20, 1, 20);
  free_ivector(jndx, 1, 20);
  free_ivector(indx, 1, 20);
  return 0;
}
```