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 = 143392 bytes
Input file size = 143674 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 129145
  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 = 129145

Output IDAT size = 129145 bytes (14247 bytes decrease)
Output file size = 129223 bytes (14451 bytes = 10.06% 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 = 82477 bytes
Input file size = 83455 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 71875
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 71528
  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 = 71528

Output IDAT size = 71528 bytes (10949 bytes decrease)
Output file size = 71606 bytes (11849 bytes = 14.20% decrease)

** Processing: figure/F13-trt-1.png
2100x2100 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 186317 bytes
Input file size = 186659 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 = 180739
  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 = 180739

Output IDAT size = 180739 bytes (5578 bytes decrease)
Output file size = 180817 bytes (5842 bytes = 3.13% 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 = 60559 bytes
Input file size = 61501 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 53126
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 52761
  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 = 52761

Output IDAT size = 52761 bytes (7798 bytes decrease)
Output file size = 52839 bytes (8662 bytes = 14.08% 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