Error(s) in re-building vignettes:
  ...
--- re-building ‘blood_loss_report.Rnw’ using knitr
** Processing: figure/MBL-Colr-pre-1.png
1800x1500 pixels, 4x8 bits/pixel, RGB+alpha
Input IDAT size = 66117 bytes
Input file size = 66291 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 58657
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 58657

Output IDAT size = 58657 bytes (7460 bytes decrease)
Output file size = 58735 bytes (7556 bytes = 11.40% decrease)


warning: solve(): system is singular (rcond: 3.13991e-19); attempting approx solution
** Processing: figure/dr-plot-1.png
2100x2100 pixels, 4x8 bits/pixel, RGB+alpha
Input IDAT size = 146629 bytes
Input file size = 146911 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 132252
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 132252

Output IDAT size = 132252 bytes (14377 bytes decrease)
Output file size = 132330 bytes (14581 bytes = 9.93% decrease)

** Processing: figure/MBL-xtree-1.png
3675x1350 pixels, 8 bits/pixel, 256 colors in palette
Reducing image to 8 bits/pixel, grayscale
Input IDAT size = 83262 bytes
Input file size = 84240 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 72531
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 72125
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 72125

Output IDAT size = 72125 bytes (11137 bytes decrease)
Output file size = 72203 bytes (12037 bytes = 14.29% decrease)

** Processing: figure/F13-trt-1.png
2100x2100 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 186358 bytes
Input file size = 186700 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5		IDAT size = 181068
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 5		IDAT size = 181068

Output IDAT size = 181068 bytes (5290 bytes decrease)
Output file size = 181146 bytes (5554 bytes = 2.97% decrease)

** Processing: figure/MBL-ztree-1.png
3750x1350 pixels, 8 bits/pixel, 256 colors in palette
Reducing image to 8 bits/pixel, grayscale
Input IDAT size = 61052 bytes
Input file size = 61994 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 53589
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 53160
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 53160

Output IDAT size = 53160 bytes (7892 bytes decrease)
Output file size = 53238 bytes (8756 bytes = 14.12% decrease)

Error: processing vignette 'blood_loss_report.Rnw' failed with diagnostics:
Running 'texi2dvi' on 'blood_loss_report.tex' failed.
LaTeX errors:
! Undefined control sequence.
l.96 \hlkwd{library}\hldef
                          {(}\hlsng{"knitr"}\hldef{)}
? 
! Emergency stop.
! Emergency stop.
l.96 
     
End of file on the terminal!

!  ==> Fatal error occurred, no output PDF file produced!
--- failed re-building ‘blood_loss_report.Rnw’

SUMMARY: processing the following file failed:
  ‘blood_loss_report.Rnw’

Error: Vignette re-building failed.
Execution halted