user: Converte this assembly snippet into its equivalent C code:

```asm
<solve>:
  endbr64
  push   %r15
  lea    -0x1(%rdx),%eax
  mov    %rdi,%r15
  push   %r14
  push   %r13
  push   %r12
  mov    %ecx,%r12d
  push   %rbp
  push   %rbx
  sub    $0x50,%rsp
  mov    %rsi,-0x60(%rsp)
  mov    %edx,-0x28(%rsp)
  mov    %eax,-0x24(%rsp)
  test   %eax,%eax
  jle    L18
  movslq %ecx,%rax
  mov    -0x24(%rsp),%edi
  lea    0x1(%rcx),%esi
  mov    %edx,-0x50(%rsp)
  lea    0x1(%rax),%rbx
  mov    %rax,0x40(%rsp)
  mov    %r15,%r13
  xor    %r14d,%r14d
  mov    %rbx,0x10(%rsp)
  shl    $0x2,%rbx
  pxor   %xmm3,%xmm3
  mov    %rax,%r12
  mov    %rbx,0x18(%rsp)
  sub    $0x4,%rbx
  mov    %edi,0x3c(%rsp)
  mov    %rbx,0x8(%rsp)
  mov    -0x60(%rsp),%rbx
  mov    %edi,-0x4c(%rsp)
  lea    0x4(%r15),%rdi
  mov    %esi,0x24(%rsp)
  mov    %rbx,%rbp
  add    $0x4,%rbx
  mov    %rax,(%rsp)
  movl   $0x0,0x20(%rsp)
  movq   $0x0,-0x20(%rsp)
  movq   $0x0,-0x68(%rsp)
  movq   $0x0,-0x30(%rsp)
  movl   $0x0,-0x70(%rsp)
  mov    %rdi,-0x8(%rsp)
  mov    %rbx,0x28(%rsp)
  mov    %ecx,%ebx
L213:
  ucomiss 0x0(%r13),%xmm3
  jp     L119
  jne    L119
  mov    -0x70(%rsp),%edi
  cmp    %edi,-0x28(%rsp)
  je     L191
  mov    -0x50(%rsp),%r11d
  mov    -0x68(%rsp),%rax
  mov    %ebx,%r10d
  mov    %r14d,%ecx
  movslq 0x20(%rsp),%rdx
  mov    %r12,-0x58(%rsp)
  not    %r10d
  lea    (%r12,%rax,1),%r8
  mov    %r11d,%eax
  mov    %r11d,%r9d
  mov    -0x28(%rsp),%r12d
  shr    $0x2,%eax
  and    $0xfffffffc,%r9d
  lea    -0x1(%rax),%esi
  mov    %edi,%eax
  sub    %r9d,%r11d
  mov    %r9d,-0x48(%rsp)
  add    %r9d,%eax
  mov    %r11d,-0x38(%rsp)
  add    $0x1,%rsi
  mov    %eax,-0x40(%rsp)
  lea    (%r15,%rdx,4),%rax
  shl    $0x4,%rsi
  mov    %rax,-0x18(%rsp)
  mov    -0x24(%rsp),%eax
  sub    %edi,%eax
  mov    -0x8(%rsp),%rdi
  add    %rdx,%rax
  lea    (%rdi,%rax,4),%rax
  mov    -0x30(%rsp),%rdi
  mov    %rax,-0x10(%rsp)
  nopw   0x0(%rax,%rax,1)
L560:
  mov    -0x60(%rsp),%rax
  movss  0x0(%rbp),%xmm0
  add    %ebx,%ecx
  addss  0x4(%rax,%rdi,4),%xmm0
  movss  %xmm0,0x0(%rbp)
  cmp    -0x70(%rsp),%r12d
  jle    L533
  cmpl   $0x1,-0x50(%rsp)
  je     L327
  cmp    $0x2,%r10d
  jbe    L327
  cmpl   $0x2,-0x4c(%rsp)
  jbe    L411
  lea    (%r15,%r8,4),%rdx
  xor    %eax,%eax
  nopl   0x0(%rax,%rax,1)
L381:
  movups 0x0(%r13,%rax,1),%xmm0
  movups (%rdx,%rax,1),%xmm5
  addps  %xmm5,%xmm0
  movups %xmm0,0x0(%r13,%rax,1)
  add    $0x10,%rax
  cmp    %rsi,%rax
  jne    L381
  mov    -0x48(%rsp),%edx
  mov    -0x50(%rsp),%eax
  cmp    %eax,%edx
  je     L533
  mov    -0x38(%rsp),%eax
  cmp    $0x1,%eax
  mov    %eax,%r11d
  mov    -0x40(%rsp),%eax
  je     L115
L184:
  mov    -0x68(%rsp),%r9
  add    %rdx,%r9
  add    %r8,%rdx
  lea    (%r15,%r9,4),%r9
  movq   (%r15,%rdx,4),%xmm0
  mov    %r11d,%edx
  movq   (%r9),%xmm1
  and    $0xfffffffe,%edx
  add    %edx,%eax
  addps  %xmm1,%xmm0
  movlps %xmm0,(%r9)
  cmp    %r11d,%edx
  je     L533
L115:
  lea    (%r14,%rax,1),%edx
  add    %ecx,%eax
  movslq %edx,%rdx
  cltq
  movss  (%r15,%rax,4),%xmm0
  addss  (%r15,%rdx,4),%xmm0
  movss  %xmm0,(%r15,%rdx,4)
L533:
  ucomiss 0x0(%r13),%xmm3
  jp     L552
  jne    L552
  add    $0x1,%rdi
  sub    %ebx,%r10d
  add    -0x58(%rsp),%r8
  cmp    %edi,%r12d
  jne    L560
L191:
  add    $0x50,%rsp
  mov    $0xffffffff,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   (%rax)
L327:
  mov    -0x20(%rsp),%rdx
  mov    -0x18(%rsp),%rax
  mov    -0x10(%rsp),%r9
  add    %r8,%rdx
  nopw   0x0(%rax,%rax,1)
L61:
  movss  (%rax),%xmm0
  addss  (%rax,%rdx,4),%xmm0
  add    $0x4,%rax
  movss  %xmm0,-0x4(%rax)
  cmp    %r9,%rax
  jne    L61
  jmp    L533
L411:
  mov    -0x50(%rsp),%r11d
  mov    -0x70(%rsp),%eax
  xor    %edx,%edx
  jmp    L184
L552:
  mov    -0x58(%rsp),%r12
L119:
  mov    -0x70(%rsp),%eax
  add    $0x1,%eax
  mov    %eax,-0x48(%rsp)
  cmp    %eax,-0x28(%rsp)
  jle    L526
  mov    0x8(%rsp),%r8
  mov    -0x4c(%rsp),%ecx
  mov    %r12,%r11
  mov    %ebx,0x38(%rsp)
  mov    0x28(%rsp),%rdi
  mov    (%rsp),%rsi
  neg    %r11
  lea    (%r8,%r13,1),%rax
  mov    %rcx,0x30(%rsp)
  mov    %rax,-0x58(%rsp)
  mov    -0x24(%rsp),%eax
  sub    -0x48(%rsp),%eax
  add    -0x30(%rsp),%rax
  lea    (%rdi,%rax,4),%r9
  mov    -0x50(%rsp),%edi
  mov    -0x58(%rsp),%rcx
  mov    %rbp,-0x58(%rsp)
  mov    %r9,%rbx
  mov    %edi,%eax
  mov    %edi,%edx
  shr    $0x2,%eax
  and    $0xfffffffc,%edx
  sub    $0x1,%eax
  mov    %edx,-0x38(%rsp)
  add    $0x1,%rax
  shl    $0x4,%rax
  mov    %rax,%r10
  mov    %edi,%eax
  mov    -0x70(%rsp),%edi
  sub    %edx,%eax
  add    %edx,%edi
  mov    %eax,-0x10(%rsp)
  mov    %edi,-0x18(%rsp)
  mov    %rbp,%rdi
  mov    %r8,%rbp
  jmp    L350
  nopl   (%rax)
L427:
  add    $0x4,%rdi
  add    %r12,%rsi
  sub    %r12,%r11
  add    %rbp,%rcx
  cmp    %rbx,%rdi
  je     L79
L350:
  movss  (%rcx),%xmm0
  mov    %esi,%edx
  mov    %esi,%eax
  ucomiss %xmm3,%xmm0
  jp     L458
  je     L427
L458:
  mov    -0x58(%rsp),%r8
  divss  0x0(%r13),%xmm0
  movss  0x4(%rdi),%xmm1
  mov    -0x70(%rsp),%r9d
  movss  (%r8),%xmm2
  mulss  %xmm0,%xmm2
  subss  %xmm2,%xmm1
  movss  %xmm1,0x4(%rdi)
  cmp    %r9d,-0x28(%rsp)
  jle    L427
  mov    %edx,%r8d
  sub    %r14d,%r8d
  sub    $0x1,%r8d
  cmp    $0x2,%r8d
  jbe    L285
  cmpl   $0x1,-0x50(%rsp)
  je     L285
  cmpl   $0x2,-0x4c(%rsp)
  jbe    L179
  movaps %xmm0,%xmm4
  xor    %edx,%edx
  shufps $0x0,%xmm4,%xmm4
  xchg   %ax,%ax
L60:
  movups 0x0(%r13,%rdx,1),%xmm2
  movups (%rcx,%rdx,1),%xmm1
  mulps  %xmm4,%xmm2
  subps  %xmm2,%xmm1
  movups %xmm1,(%rcx,%rdx,1)
  add    $0x10,%rdx
  cmp    %r10,%rdx
  jne    L60
  mov    -0x38(%rsp),%r8d
  mov    -0x50(%rsp),%edx
  cmp    %edx,%r8d
  je     L427
  mov    -0x10(%rsp),%edx
  cmp    $0x1,%edx
  mov    %edx,-0x40(%rsp)
  mov    -0x18(%rsp),%edx
  je     L515
L244:
  mov    -0x30(%rsp),%r9
  movaps %xmm0,%xmm4
  shufps $0xe0,%xmm4,%xmm4
  add    %rsi,%r9
  add    %r8,%r9
  add    -0x68(%rsp),%r8
  movq   (%r15,%r8,4),%xmm2
  lea    (%r15,%r9,4),%r9
  movq   (%r9),%xmm1
  mulps  %xmm4,%xmm2
  subps  %xmm2,%xmm1
  movlps %xmm1,(%r9)
  mov    -0x40(%rsp),%r9d
  mov    %r9d,%r8d
  and    $0xfffffffe,%r8d
  add    %r8d,%edx
  cmp    %r9d,%r8d
  je     L427
L515:
  add    %edx,%eax
  add    %r14d,%edx
  movslq %edx,%rdx
  cltq
  mulss  (%r15,%rdx,4),%xmm0
  movss  (%r15,%rax,4),%xmm1
  subss  %xmm0,%xmm1
  movss  %xmm1,(%r15,%rax,4)
  jmp    L427
L79:
  mov    -0x58(%rsp),%rbp
  mov    0x38(%rsp),%ebx
L526:
  mov    -0x20(%rsp),%rax
  add    %r12,(%rsp)
  add    %ebx,%r14d
  add    $0x4,%rbp
  mov    0x10(%rsp),%rdi
  addq   $0x1,-0x30(%rsp)
  sub    %r12,%rax
  add    %rdi,-0x68(%rsp)
  add    0x18(%rsp),%r13
  sub    $0x1,%rax
  mov    0x24(%rsp),%edi
  subl   $0x1,-0x4c(%rsp)
  add    %edi,0x20(%rsp)
  mov    -0x24(%rsp),%edi
  subl   $0x1,-0x50(%rsp)
  mov    %rax,-0x20(%rsp)
  cmp    %edi,-0x48(%rsp)
  je     L368
  mov    -0x48(%rsp),%eax
  mov    %eax,-0x70(%rsp)
  jmp    L213
L285:
  add    -0x30(%rsp),%edx
  mov    -0x8(%rsp),%r8
  movslq %edx,%rdx
  lea    (%r15,%rdx,4),%rax
  add    0x30(%rsp),%rdx
  lea    (%r8,%rdx,4),%rdx
  nopl   (%rax)
L40:
  movss  (%rax,%r11,4),%xmm2
  movss  (%rax),%xmm1
  add    $0x4,%rax
  mulss  %xmm0,%xmm2
  subss  %xmm2,%xmm1
  movss  %xmm1,-0x4(%rax)
  cmp    %rdx,%rax
  jne    L40
  jmp    L427
L37:
  mov    -0x50(%rsp),%esi
  mov    -0x38(%rsp),%r10
  lea    (%r15,%rdx,1),%r8
  movslq -0x68(%rsp),%r9
  lea    (%r10,%rsi,4),%r10
  mov    %rcx,%rsi
  xchg   %ax,%ax
L467:
  movss  -0x4(%r8),%xmm0
  divss  (%r15,%r9,4),%xmm0
  movss  (%rsi),%xmm1
  add    $0x4,%rsi
  mulss  -0x4(%rcx,%rdx,1),%xmm0
  add    %rax,%r8
  subss  %xmm0,%xmm1
  movss  %xmm1,-0x4(%rsi)
  cmp    %r10,%rsi
  jne    L467
L174:
  mov    -0x50(%rsp),%esi
  mov    -0x4c(%rsp),%r10d
  mov    %r11,%rdx
  mov    -0x48(%rsp),%r8
  add    %r10d,-0x68(%rsp)
  add    %r8,-0x70(%rsp)
  subq   $0x4,-0x58(%rsp)
  test   %esi,%esi
  jne    L388
L18:
  mov    -0x28(%rsp),%eax
  test   %eax,%eax
  jle    L271
  movslq %r12d,%rcx
  movslq -0x28(%rsp),%rdx
  xor    %r8d,%r8d
  mov    -0x60(%rsp),%rbx
  add    $0x1,%rcx
  mov    %r8,%rdi
  lea    0x0(,%rcx,4),%rsi
  mov    %rdx,%r11
  sub    $0x1,%rdx
  mov    %rsi,%rax
  imul   %rdx,%rax
  test   %rsi,%rsi
  lea    (%rbx,%rdx,4),%rdx
  cmovs  %rax,%rdi
  add    %r15,%rdi
  cmp    %rdx,%rdi
  seta   %dl
  test   %rsi,%rsi
  cmovs  %r8,%rax
  add    %r15,%rax
  cmp    %rax,%rbx
  seta   %al
  or     %al,%dl
  je     L386
  cmpl   $0x2,-0x24(%rsp)
  jbe    L386
  mov    %r11d,%edi
  mov    %rcx,%r8
  lea    (%rcx,%rcx,2),%rcx
  mov    %rbx,%rdx
  shr    $0x2,%edi
  shl    $0x4,%r8
  mov    %r15,%rax
  sub    $0x1,%edi
  shl    $0x2,%rcx
  shl    $0x4,%rdi
  lea    0x10(%rbx,%rdi,1),%rdi
L333:
  movss  (%rax,%rcx,1),%xmm1
  movss  (%rax,%rsi,2),%xmm0
  add    $0x10,%rdx
  movss  (%rax,%rsi,1),%xmm2
  unpcklps %xmm1,%xmm0
  movss  (%rax),%xmm1
  add    %r8,%rax
  unpcklps %xmm2,%xmm1
  movlhps %xmm0,%xmm1
  movups -0x10(%rdx),%xmm0
  divps  %xmm1,%xmm0
  movups %xmm0,-0x10(%rdx)
  cmp    %rdi,%rdx
  jne    L333
  mov    -0x28(%rsp),%eax
  mov    %r12d,%esi
  mov    %eax,%ebx
  and    $0xfffffffc,%ebx
  mov    %ebx,%edx
  imul   %ebx,%esi
  mov    %eax,%ebx
  cmp    %eax,%edx
  je     L271
  mov    -0x60(%rsp),%rdi
  mov    %edx,%eax
  lea    (%rdi,%rax,4),%rcx
  lea    (%rsi,%rdx,1),%eax
  add    %r12d,%esi
  cltq
  movss  (%rcx),%xmm0
  divss  (%r15,%rax,4),%xmm0
  lea    0x1(%rdx),%eax
  movss  %xmm0,(%rcx)
  cmp    %eax,%ebx
  jle    L271
  add    %esi,%eax
  add    $0x2,%edx
  movss  0x4(%rcx),%xmm0
  cltq
  divss  (%r15,%rax,4),%xmm0
  lea    (%r12,%rsi,1),%eax
  movss  %xmm0,0x4(%rcx)
  cmp    %ebx,%edx
  jge    L271
  add    %eax,%edx
  movss  0x8(%rcx),%xmm0
  movslq %edx,%rax
  divss  (%r15,%rax,4),%xmm0
  movss  %xmm0,0x8(%rcx)
L271:
  xor    %eax,%eax
L130:
  add    $0x50,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L179:
  mov    -0x50(%rsp),%edx
  xor    %r8d,%r8d
  mov    %edx,-0x40(%rsp)
  mov    -0x70(%rsp),%edx
  jmp    L244
L368:
  mov    %ebx,%r12d
  mov    %ebx,%eax
  mov    -0x24(%rsp),%ebx
  movslq -0x28(%rsp),%rcx
  not    %eax
  mov    %r12d,%esi
  xor    %r14d,%r14d
  mov    %eax,-0x4c(%rsp)
  mov    %ebx,%eax
  lea    0x0(,%rcx,4),%rdx
  neg    %esi
  imul   %r12d,%eax
  movslq %esi,%rsi
  lea    -0x4(%rdx),%r11
  lea    -0x4(,%rsi,4),%r13
  mov    %r13,-0x48(%rsp)
  add    %eax,%ebx
  cltq
  add    %rcx,%rax
  mov    -0x60(%rsp),%rcx
  mov    %ebx,-0x68(%rsp)
  lea    (%r15,%rax,4),%r9
  lea    (%r15,%r11,1),%rax
  mov    0x40(%rsp),%rbx
  lea    0x4(%rcx),%rsi
  mov    %rax,-0x58(%rsp)
  mov    0x8(%rsp),%rax
  mov    %rsi,-0x38(%rsp)
  lea    0x10(%rcx),%rsi
  shl    $0x4,%rbx
  mov    %r9,-0x70(%rsp)
  lea    (%rax,%rax,2),%rdi
  mov    %rsi,-0x40(%rsp)
  mov    0x3c(%rsp),%esi
L78:
  test   %esi,%esi
  jle    L369
  lea    -0x1(%rsi),%r10d
  mov    %esi,%r9d
  mov    %r10d,-0x50(%rsp)
  mov    -0x70(%rsp),%r10
  lea    0x0(,%r9,4),%r13
  sub    $0x1,%r9
  lea    (%rcx,%r13,1),%rbp
  mov    %r9,%r8
  sub    $0x4,%r10
  imul   %rax,%r8
  cmp    %r10,%rbp
  setbe  %bpl
  cmp    -0x70(%rsp),%rcx
  setae  %r10b
  or     %r10d,%ebp
  test   %rdx,%rdx
  setle  %r10b
  cmp    %r11,%r13
  setle  %r13b
  or     %r13d,%r10d
  and    %ebp,%r10d
  cmpl   $0x2,-0x50(%rsp)
  seta   %bpl
  test   %bpl,%r10b
  je     L37
  test   %r12d,%r12d
  lea    (%rcx,%r9,4),%r10
  mov    %r14,%r9
  cmovs  %r8,%r9
  add    %r11,%r9
  add    %r15,%r9
  cmp    %r9,%r10
  setb   %r9b
  test   %r12d,%r12d
  cmovs  %r14,%r8
  add    %r11,%r8
  add    %r15,%r8
  cmp    %r8,%rcx
  seta   %r8b
  or     %r9b,%r8b
  je     L37
  movslq -0x68(%rsp),%r8
  movss  -0x4(%rcx,%rdx,1),%xmm3
  mov    %rcx,%r9
  movss  (%r15,%r8,4),%xmm4
  lea    (%r15,%r8,4),%r13
  mov    %esi,%r8d
  shufps $0x0,%xmm3,%xmm3
  shr    $0x2,%r8d
  lea    -0x1(%r8),%r10d
  mov    -0x58(%rsp),%r8
  shufps $0x0,%xmm4,%xmm4
  shl    $0x4,%r10
  add    -0x40(%rsp),%r10
  nopl   0x0(%rax)
L267:
  movss  (%r8,%rdi,1),%xmm0
  movss  (%r8,%rax,2),%xmm1
  add    $0x10,%r9
  movss  (%r8,%rax,1),%xmm2
  unpcklps %xmm0,%xmm1
  movss  (%r8),%xmm0
  add    %rbx,%r8
  unpcklps %xmm2,%xmm0
  movlhps %xmm1,%xmm0
  movups -0x10(%r9),%xmm1
  divps  %xmm4,%xmm0
  mulps  %xmm3,%xmm0
  subps  %xmm0,%xmm1
  movups %xmm1,-0x10(%r9)
  cmp    %r10,%r9
  jne    L267
  mov    %esi,%r9d
  mov    %r12d,%r8d
  and    $0xfffffffc,%r9d
  imul   %r9d,%r8d
  cmp    %esi,%r9d
  je     L252
  lea    (%rsi,%r8,1),%ebp
  mov    %r9d,%r10d
  add    %r12d,%r8d
  movslq %ebp,%rbp
  lea    (%rcx,%r10,4),%r10
  movss  (%r15,%rbp,4),%xmm0
  divss  0x0(%r13),%xmm0
  mulss  -0x4(%rcx,%rdx,1),%xmm0
  lea    0x1(%r9),%ebp
  movss  (%r10),%xmm1
  subss  %xmm0,%xmm1
  movss  %xmm1,(%r10)
  cmp    %ebp,%esi
  jle    L252
  lea    (%rsi,%r8,1),%ebp
  movss  0x4(%r10),%xmm1
  add    $0x2,%r9d
  add    %r12d,%r8d
  movslq %ebp,%rbp
  movss  (%r15,%rbp,4),%xmm0
  divss  0x0(%r13),%xmm0
  mulss  -0x4(%rcx,%rdx,1),%xmm0
  subss  %xmm0,%xmm1
  movss  %xmm1,0x4(%r10)
  cmp    %r9d,%esi
  jle    L252
  add    %esi,%r8d
  movss  0x8(%r10),%xmm1
  movslq %r8d,%rsi
  movss  (%r15,%rsi,4),%xmm0
  divss  0x0(%r13),%xmm0
  mulss  -0x4(%rcx,%rdx,1),%xmm0
  subss  %xmm0,%xmm1
  movss  %xmm1,0x8(%r10)
L252:
  mov    -0x4c(%rsp),%r10d
  mov    -0x48(%rsp),%r8
  mov    %r11,%rdx
  add    %r10d,-0x68(%rsp)
  mov    -0x50(%rsp),%esi
  add    %r8,-0x70(%rsp)
  subq   $0x4,-0x58(%rsp)
L388:
  sub    $0x4,%r11
  jmp    L78
L369:
  sub    $0x1,%esi
  mov    %esi,-0x50(%rsp)
  jmp    L174
L386:
  mov    -0x60(%rsp),%rdx
  mov    -0x24(%rsp),%ecx
  mov    %r15,%rax
  lea    0x4(%rdx,%rcx,4),%rcx
L485:
  movss  (%rdx),%xmm0
  add    $0x4,%rdx
  divss  (%rax),%xmm0
  add    %rsi,%rax
  movss  %xmm0,-0x4(%rdx)
  cmp    %rdx,%rcx
  jne    L485
  xor    %eax,%eax
  jmp    L130
```

assistant: ```c
solve(matrix, vector, irow, ilead) int irow, ilead;
float (*matrix)[];
float (*vector)[];
{
  float quotient;
  int i, j, k;
  int mpi, mpj, mpk;
  mpi = 0;
  for (i = 0; i < irow - 1; i++) {
    j = i;
    mpj = mpi;
    while ((*matrix)[mpi + i] == 0) {
      if (j == irow) {
        return (-1);
      }
      j++;
      mpj += ilead;
      (*vector)[i] += (*vector)[j];
      for (k = i; k < irow; k++) {
        (*matrix)[mpi + k] += (*matrix)[mpj + k];
      }
    }
    mpj = mpi + ilead;
    for (j = i + 1; j < irow; j++) {
      if ((*matrix)[mpj + i] != 0) {
        quotient = (*matrix)[mpj + i] / (*matrix)[mpi + i];
        (*vector)[j] -= (*vector)[i] * quotient;
        for (k = i; k < irow; k++) {
          (*matrix)[mpj + k] -= (*matrix)[mpi + k] * quotient;
        }
      }
      mpj += ilead;
    }
    mpi += ilead;
  }
  mpi = 0;
  for (i = 0; i < irow - 1; i++) {
    k = irow - i - 1;
    mpj = 0;
    mpk = k * ilead;
    for (j = 0; j < k; j++) {
      (*vector)[j] -= (*matrix)[mpj + k] / (*matrix)[mpk + k] * (*vector)[k];
      mpj += ilead;
    }
  }
  mpi = 0;
  for (i = 0; i < irow; i++) {
    (*vector)[i] /= (*matrix)[mpi + i];
    mpi += ilead;
  }
  return (0);
}
```